Read our fact check of the final presidential debate

A reminder… The Supreme Court has one vacancy, due to the death of Justice Antonin Scalia in February. President Obama nominated Merrick Garland, the chief judge of the U.S. Court of Appeals for the District of Columbia Circuit, to replace Scalia. Senate Republicans have so far refused to consider Garland's nomination. The next president could appoint two or perhaps even three justices to the Supreme Court.— Daniel Bush, Digital politics editor

More on that… The opening question is one of the most tangible and most watched issues at stake this election. According to a poll from the Pew Research Center in July, 65 percent of voters consider Supreme Court appointments "very important" to their vote.— Lisa Desjardins, Political correspondent

A reminder… Hillary Clinton has not released a list of potential Supreme Court nominees. She has said she would use a "litmus test" for potential nominees to ensure that they share her views on issues like gun control and abortion. Clinton has also said that the Senate should hold a vote on the nomination of Merrick Garland, chief judge of the U.S. Court of Appeals for the District of Columbia.

A reported shortlist of possible Clinton nominees includes Garland, D.C. Circuit Court Judge Sri Srinivasan, and 9th Circuit Judge Paul Watford, among others. — Daniel Bush, Digital politics editor

A reminder… Clinton may be on the record urging the Senate to hold a confirmation vote on Garland. But if there is no vote before the election — and Senate Republicans insist it won't happen — would a President Hillary Clinton re-nominate Garland?

She was asked about that during an interview with the Tom Joyner Morning Show that aired in September. Here's how The Washington Post described her response:

"She also declined to say whether she would ask President Obama to pull the stalled Supreme Court nomination of Merrick Garland if she wins, clearing the way for her own choice. A host suggested perhaps a black woman in the place of the white Garland. 'We should stick with one president at a time,' Clinton said. 'If I have the opportunity to name any Supreme Court appointments, I'm going to look broadly and widely for people who represent the diversity of our country, who bring some common sense, real world experience.' "

— Geoffrey Guray, Politics reporter/producer

More on that…In May, Donald Trump released a list of 11 potential Supreme Court nominees that he might appoint as president. The list — which consisted of eight white men and three white women — included several well-known conservative judges.

In response to criticism that the list lacked diversity, Trump put out a second list in September with 10 more potential nominees. They included an African-American state judge and a federal judge who was born in Venezuela.— Daniel Bush, Digital politics editor

Here's what we know…Trump does not seem certain, saying "probably," but he is right. Over the past two years, Chicago has seen the highest rate of homicides and of non-fatal shootings of the past, according to the Major Cities Chief Association. (See this well-done report by our colleagues at ABC.) — Lisa Desjardins, Political correspondent

More on that…Some perspective here: As the Washington Post, NPR and others have pointed out before, most abortions take place much earlier in pregnancy, well before nine months. The Guttmacher Institute has published data saying that nearly 90 percent take place in the first 12 weeks. Just about 1 percent happen after 21 weeks. It should be noted that in the late 90s, Trump said he didn't want to ban late-term abortions. In fact, in 1999, Trump told Meet the Press that while he personally disliked abortion, "I'm very pro-choice." — Murrey Jacobson, National affairs editor

More on that… The late Justice Antonin Scalia authored the Court's 2008 ruling in District of Columbia v. Heller. Some critical sentences:

"There seems to us no doubt, on the basis of both text and history, that the Second Amendment conferred an individual right to keep and bear arms."

But the ruling also said there might be limits:

"Like most rights, the right secured by the Second Amendment is not unlimited … Nothing in our opinion should be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms."

And yes, the court went on to say that the D.C. handgun ban at issue in the case was too broad.

The Supreme Court hasn't ruled since then, to clarify what other kinds of restrictions may be placed on the Second Amendment right to bear arms.

Want to find out more about what the "Heller" ruling did and didn't say? Any legal eagles out there can read the decision itself. — Geoffrey Guray, Politics reporter/producer

More on that…It is true that on August 30, the government of Prime Minister Shinzo Abe requested another increase in military spending to expand missile defenses, to guard against China's moves on islands claimed by Japan, and against North Korea's nuclear weapons program. The picture in Saudi Arabia is more mixed. The Kingdom recently announced plans to increase defense spending by 27 percent over five years, (although its $48.7 billion military budget in 2015 is actually a 2 percent decrease, according to the consultancy IHS Jane's Aerospace, Defense and Security. )

But it is not true that these increases and planned increases came in response to Trump's attack on U.S. allies for failing to pay their fair share. The proposed Japanese hike would be its fifth-straight annual increase. Analysts ascribe Saudi Arabia's planned hikes to the more assertive Saudi foreign policy adopted since King Salman took the throne last year, and embarked on a war in Yemen against Shiite Houthi rebels, seen as proxies of Saudi arch-rival Iran. — Margaret Warner, Chief foreign affairs correspondent

More on that…Independent analysts do not agree with Clinton's characterization of what her plans would add to the debt at all. The Committee for a Responsible Federal Budget, a budget/debt watchdog group (sometimes considered a budget hawk group), estimate her policies would add roughly $200 billion to the debt over the next decade. That said, Trump's plans would add far more by the committee's estimates: More than $5 trillion in additional debt over the same timeframe. In a blog posted earlier today, the group noted other differences between the two this way: "While Clinton has put forth a serious effort to pay for her proposals, neither candidate would address the unsustainable trajectory of our nation's debt — and Trump would substantially worsen it." — Murrey Jacobson, National affairs editor

Here's what we know… This marks a reversal from Trump just weeks ago and from his campaign as recently as hours before this debate. Trump has now publicly left doubt as to whether he would accept the results of the election. He's emphasized repeatedly in recent days that he believes the election could be rigged by the media, the elites, the Democratic Party and other institutions. But this is the furthest he has gone on this in recent days. After the first debate, Trump said he would "absolutely" accept the results. He later left doubt in an interview with the New York Times. But just hours before the debate tonight, his running mate, Governor Mike Pence, told CNN's Dana Bash, "We'll certainly accept the outcome of this election." — Murrey Jacobson, National affairs editor

Here's what we know… The key economic issue is arguably whether so-called trickle-down economics actually works — or will work going forward. Trump suggests that growth will surge as much as 6 percent a year. No economist I've ever met thinks that's plausible.

Trump is banking on economic growth. Clinton, to the extent that she's paying for what she proposes — infrastructure spending, college tuition cuts — will pay for it with taxes on those who make hundreds of thousands a year and up. — Paul Solman, Senior correspondent and economist

Here's what we know… Donald Trump says the Immigration and Customs Enforcement, ICE, has endorsed him for president. However, the endorsement actually comes from the National Immigration and Customs Enforcement Council, a private union representing immigration and law enforcement workers. ICE, the federal agency, has not endorsed a candidate for president.

According to the Pew Research Center, when it comes immigration reform, the American public wants to address the status of the more than 11 million undocumented immigrants in the country and stronger borders.

When asked which immigration initiative should be a priority, 45 percent of Americans said they want equal attention paid to border security and a pathway to citizenship. When those who responded "both" were asked to choose between the two, 79 percent of Americans said a pathway to U.S. citizenship for undocumented immigrants was a greater priority than better border security and law enforcement.

— Kenya Downs, Digital reporter for Race Matters

More on that… There are a series of nuclear weapons treaties going back decades between the U.S. and Russia (and the Soviet Union.) Among the most recent: the so-called "new "START" treaty of 2011. That's apparently what Donald J. Trump was referring to with the malapropism – calling it the "START up". But his underlying point — quoted above — is, technically, correct. Russia has deployed more nuclear warheads than the United States since 2010, and by a significant number.

According to the U.S. State Department, the Russians have a whopping 429 more nuclear warheads deployed across an array of delivery platforms than the U.S. However, more concerning in respect to the "new START" treaty is the fact that the Russians have 240-plus more nuclear weapons deployed than the 1,550 weapons allowed by the 2011 treaty. This may change, however, if — and a big if at this moment — the treaty is followed. The next marker in the "New START" is 2018, in early February then, when the full implementation is due. But a bad sign has lately emerged: the Russians are proceeding with the testing of a land-based cruise missile system that could end up violating the landmark, Reagan/Gorbachev-era "INF" treaty. That pact, a signal achievement of the late Cold War, governs intermediate-range nuclear forces, that helped de-escalate the nuclear standoff in Europe. The U.S. first reported a possible violation of this treaty two years ago; violations the Russians deny.

— Morgan Till, Senior foreign affairs producer

Here's what we know… It's true that the Obama administration has overseen a dramatic increase in deportations. More than 2.5 million people have been deported during Obama's presidency, a 23 percent increase over the rate during George W. Bush's term, data from the Department of Homeland Security shows. More than 90 percent of those deported under Obama's directives had previously been convicted of crimes.

— Travis Daub, Director of digital

More on that… Despite all the hubbub about energy, manufacturing and international trade during this election cycle, the industry predicted to see the largest job growth in the next 20 years is health care, according to the U.S. Bureau of Labor Statistics. Medical assistance alone is expected to grow by 23 percent, as baby boomers leave the workforce. The construction industry ranks second on the BLS growth list, while private educational services at colleges and universities come in third. Regardless, BLS predicts that 11 of the 15 fastest growing occupations will require some level of post-secondary education.

— Nsikan Akpan, Digital science producer

More on that… This is the key economic difference: Trump believes that tax cuts will incentivize the rich to invest and create jobs. Clinton doesn't buy it, and there is scant evidence that tax cuts have created jobs in recent decades.

— Paul Solman, Senior correspondent and economist

More on that… Clinton is mostly correct about Russian President Vladimir Putin's apparent preference for Trump. Members of the intelligence community issued a statement agreeing that Russian actors — with approval at the highest levels — staged cyberattacks on the Democratic National Committee and Democratic Congressional Campaign Committee, released by anonymous sites like "Guccifer 2.0." It's also true the Trump invited Russia to hack and release the missing 30,000 emails from Clinton's time as secretary of state.

The intelligence community's statement didn't include the WikiLeaks release of emails of Clinton confidants, including longtime adviser John Podesta. The leaks included purported quotes from speeches she gave to private Wall Street and banking groups for six-figure fees, including one endorsing "open borders."

It is also true that Trump has applauded Putin as a strong leader, and has said it's good for the U.S. if Russia takes care of ISIS in Syria. And he has refrained from criticizing Putin's bombing campaign against civilians in Syria, and his 2014 annexing of Crimea and stirring up war in Eastern Ukraine.

— Margaret Warner, Chief foreign affairs correspondent

Here's what we know… Actually, Clinton underestimated that number. The Clinton Health Access Initiative has provided HIV-AIDS medicine to 11.8 million, which represents closer to 70 percent of people treated worldwide. In May, UNAIDS announced 17 million overall have access to HIV meds.

— Nsikan Akpan, Digital science producer

Here's what we know… Trump's comment and Chris Wallace's question on the matter refers to an Oct. 11 ABC News report that reviewed emails obtained by the Republican National Committee through a Freedom of Information Act request. The story outlines how friends of Bill Clinton and Clinton Foundation donors made aid requests to the foundation just after the 2010 Haiti earthquake. The Clinton Foundation subsequently forwarded those requests to the State Department, which Hillary Clinton ran at the time as Secretary of State.

Here's the gist. The State Department did most certainly assist people connected to the Clinton Foundation in the immediate aftermath of the earthquake. But neither the ABC News report nor a follow-up investigation by the State Department found evidence that government officials helped foundation donors or Bill Clinton's friends obtain contracts.

— Nsikan Akpan, Digital science producer

More on that…While the Clinton Foundation provided millions of dollars toward Haiti's recovery from the 2010 earthquake, many of the funded projects were incomplete or controversial. Haitian and Haitian-Americans have been critical of an uncompleted $2 million housing project and $170 million in USAID funding meant for earthquake relief that instead went toward the construction of an industrial park built 82 miles away from the earthquake zone. An investigation also revealed that Hillary Clinton's brother, Tony Rodham, may have used Clinton Foundation connections to gain access to a controversial gold mining project in Haiti. Haitian activists protested outside the Clinton Foundation headquarters in New York City last year.

However, most of the Trump campaign's criticism of the Clinton Foundation's work in Haiti stems from accusations that the foundation raised hundreds of millions of dollars meant for a hospital that was never built. That claim is unsubstantiated.

— Kenya Downs, Digital reporter/producer

Here's what we know… The Obama Administration claims that the Affordable Care Act extended the life of the Medicare Trust fund to 2028 — still not terribly far away — through "reductions in waste, fraud and abuse."

Conservative analysts say Medicare's future does indeed look brighter than it did before Obamacare, but they're skeptical about how much credit the law should receive given the overall trends that existed in the health care industry before passage of the ACA.​

To Clinton's point that scrapping the law wouldn't necessarily save the country money, the Congressional Budget Office recently estimated that repealing Obamacare would increase the federal deficit by $137 to $353 billion between 2016 and 2025.

— Jason Kane, health producer

Here's what we know… While rates will rise dramatically in the coming year — surging by at least 30 percent in eight states — increases of "70, 80" percent will not be common. Federal officials expect 13.8 million people to sign up for coverage in the open enrollment period that begins Nov. 1. That's an increase of 9 percent over the last open enrollment season. Many will be shielded from the rate increases through subsidies from the federal government.​

— Jason Kane, health producer

Here's what we know… This has indeed become an even more central part of the Clinton agenda since the primaries ended and she moved closer to adopting Sanders' position on this. This would be true for students attending public colleges — assuming she could get it passed at a cost of $350 billion over 10 years. A number of advocates and experts say it could make a crucial difference for students who cannot afford higher education. But other experts say it could raise the overall price and burden on the government — even if students are protected from the costs. They believe universities and colleges would raise tuition again once they see the federal government is paying for a big part of it. Some studies have already found that colleges raise prices when federal subsidies increase.

It's also not clear how much of an impact the Clinton plan would have on state funding and aid cuts, which have had a pronounced effect on the rise in student debt over time.

Clinton could try to pass a law limiting the rise in tuition, but it's not entirely clear that she intends to do so.

— Murrey Jacobson, National affairs editor