AMNA NAWAZ: Dick Cheney, one of the most influential and polarizing vice presidents in American history, has died at the age of 84.

He served alongside then-President George W. Bush for two terms, which saw the 9/11 attacks and the start of two major wars.

In a statement today, President Bush wrote -- quote -- "Dick was a calm and steady presence in the White House amid great national challenges."

Cheney's family said he passed away yesterday due to complications from pneumonia, along with cardiac and vascular disease.

John Yang looks back at his life and legacy with this report.

JOHN YANG: As President George W. Bush's number two, Dick Cheney emerged as one of the most powerful and controversial vice presidents to date.

The eight years he was in office were some of the most consequential in American history, the 9/11 attacks, wars in Iraq and Afghanistan, and the war on terror.

Cheney was at the center of it all.

DICK CHENEY, Former Vice President of the United States: I basically was given pretty much free rein to get involved in whatever I wanted to get involved in, participate in the meetings I wanted to participate in.

JOHN YANG: He was most involved in national security, especially the controversial Iraq War.

Cheney led the effort to convince the American public of a contentious argument.

DICK CHENEY: Simply stated, there is no doubt that Saddam Hussein now has weapons of mass destruction.

There is no doubt that he is amassing them to use against our friends, against our allies, and against us.

JOHN YANG: When no weapons of mass destruction were found, Cheney was unapologetic.

WOLF BLITZER, CNN Anchor: So no regrets about Iraq?

DICK CHENEY: I think we made the - - exactly the right decisions.

JOHN YANG: Richard Bruce Cheney was born in Nebraska and grew up in Wyoming.

He went to Yale University on a full scholarship, but flunked out twice.

He eventually got his bachelor's and master's degrees in Wyoming.

He was pursuing his Ph.D.

with an eye on an academic career, when a one-year fellowship on Capitol Hill changed the direction of his life.

In time, he became President Gerald Ford's White House chief of staff, at 34, the youngest ever.

He was so low-key his Secret Service code name was Backseat.

Following Ford's loss to Jimmy Carter in 1976, Cheney returned to Wyoming to run for the state's lone U.S.

House seat.

During that campaign, Cheney had his first heart attack when he was just 37.

For the next three decades, he struggled with coronary artery disease, four more heart attacks and quadruple bypass surgery before a 2012 heart transplant.

Back then, his wife, Lynne, stood in until he could resume campaigning.

He won with 59 percent of the vote, the smallest margin of his seven election wins.

His amiable, moderate personality cloaked the positions of a staunch conservative, for cutting taxes and more defense spending, and against abortion and gun laws.

He rose in the leadership and in 1988 was elected whip, the number two House Republican.

He wasn't in the job long.

After the Senate rejected John Tower to be President George H.W.

Bush's defense secretary, the new president turned to Cheney.

GEORGE H.W.

BUSH, Former President of the United States: He's a thoughtful man, a quiet man, a strong man, approaches public policy with vigor and determination and diligence.

JOHN YANG: Despite a lack of military experience -- he got five Vietnam War draft deferments -- he sailed through the Senate 92-0.

At the Pentagon, Cheney quickly asserted himself, bypassing more than a dozen more senior generals to select Colin Powell to be Joint Chiefs chairman, the first Black person and the youngest in that job.

Together, they oversaw the U.S.

invasion of Panama, the pivot from Cold War footing and the first Iraq War after Iraqi President Saddam Hussein invaded Kuwait.

As U.S.

forces gathered in Saudi Arabia in August 1990, Cheney explained the U.S.

interests at stake on the "News Hour."

DICK CHENEY: We're there because if Saddam Hussein, who is, I would argue, a far more frightful creature than most rulers you will find any place in the world today, were to take control of the world's supply of energy with his enormous military capability, with the prospect he would acquire nuclear weapons, that he would have a strangle to hold on the economy of the United States and the rest of the world.

And we cannot afford that.

That's why we're there.

JOHN YANG: It took U.S.

forces just 100 hours to drive Iraq out of Kuwait.

President Bush rejected calls to push on to Baghdad and topple Hussein.

DICK CHENEY: We had an objective.

We achieved our objective and we weren't going any further.

JOHN YANG: After Bush was defeated for reelection by Bill Clinton in 1992, Cheney briefly considered running for president.

DICK CHENEY: The more I thought about it, the more I decided this is not something for me.

JOHN YANG: Instead, he became the head of Halliburton, one of the world's biggest oil services firms.

His time there drew scrutiny during the 2003 Iraq War, when Halliburton got multibillion-dollar Pentagon contracts.

Questions were raised, but no evidence of wrongdoing was ever uncovered.

Cheney's return to public service was unexpected.

In July 2000, he arrived at George W. Bush's Texas ranch with two binders of research into potential running mates that Bush had asked him to gather.

It turns out there was no need.

Bush asked Cheney to join the ticket.

GEORGE W. BUSH, Former President of the United States: Gradually, I realized that the person who was best qualified to be my vice presidential nominee was working by my side.

JOHN YANG: Years later, Cheney acknowledged that he was an unconventional choice, a 60-year-old with heart disease.

DICK CHENEY: If health was the only criteria, go get a 30-year-old.

That's not what he was after.

What he was after was somebody with experience.

JOHN YANG: Especially the foreign policy experience and the years operating the levers of power in Washington, both things Bush lacked.

During the drawn-out Florida recount that decided the election, Cheney assembled a team that would become the next Bush administration.

He also suffered his fourth heart attack.

Just eight months into the new presidency, everything changed with the September 11 attacks.

DICK CHENEY: All of a sudden, the door to my office burst open.

And one of my agents, a Secret Service agent named Jimmy Scott, came bursting in, grabbed the back of my belt and literally lifted me out of the chair and propelled me out of the room.

JOHN YANG: President Bush was in the air after visiting an elementary school in Florida and communications with Air Force One were spotty.

In the underground White House emergency operations center, it was Cheney others turned to for decisions.

At one point, an airliner appeared to be heading toward the White House.

An Air Force official asked if it should be shot down.

DICK CHENEY: And I said yes.

I gave that order.

I couldn't take a poll.

I didn't have time to call the president.

If it was going to happen, it was going to happen very fast.

So I never hesitated.

JOHN YANG: In the following days, he played a central role in shaping the U.S.

response.

The weekend after the attacks, he spoke with Tim Russert on NBC's "Meet the Press."

DICK CHENEY: We also have to work those -- sort of the dark side, if you will.

We're going to spend time in the shadows and in the intelligence world.

A lot of what needs to be done here will have to be done quietly without any discussion.

JOHN YANG: Intelligence identified Osama bin Laden as being behind the attacks.

A month after 9/11, U.S.

forces went to war in Afghanistan to root him out.

DICK CHENEY: We will hold those who harbor terrorists, those who provide sanctuary to terrorists responsible for their acts.

JOHN YANG: Troops defeated the Taliban, but bin Laden slipped across the border to Pakistan.

Then, more controversially, the administration turned its attention to Iraq, and Cheney again had a leading role in a military operation against Saddam Hussein.

On "Meet the Press," he predicted another quick triumph.

Asked by moderator Tim Russert if he thought Americans were prepared for a long battle with many U.S.

casualties, Cheney said: "I don't think it's likely to unfold that way, because I really do believe we will be greeted as liberators."

Hussein was toppled in just three weeks, but U.S.

forces remained in Iraq for eight years.

More than 3,400 troops were killed in hostilities and nearly 32,000 wounded.

As suspected terrorists were captured on the battlefield, Cheney endorsed so-called enhanced interrogation techniques, including water-boarding.

DICK CHENEY: Techniques we came up with, up to and including water-boarding, and that was the most significant, but specifically had been deemed not to constitute torture and therefore to be within the safeguards of our international agreements.

Not everybody agreed with that, but we did it by the book.

JOHN YANG: A 2014 Senate Intelligence Committee report concluded the techniques did not yield any significant intelligence.

As the 2004 election approached, Cheney had become a lightning rod for criticism.

He offered to step down from the ticket, an offer Bush said he considered, but rejected.

In the second term, Cheney said his role was diminished.

DICK CHENEY: In the last term, especially given my general view of the world, and I was more hawkish than most, that the president didn't accept my advice as much as he had in the first term.

JOHN YANG: Bush and Cheney's relationship, always more professional than personal, was strained in the closing days of the administration over the president's refusal to pardon longtime Cheney aide Scooter Libby.

He'd been convicted of lying to a grand jury during an FBI investigation into the leak of a CIA operative's name.

Returning to private life, Cheney became a fierce critic of President Barack Obama, and during the next administration, he backed his elder daughter, Representative Liz Cheney, when she criticized President Donald Trump's efforts to overturn the 2020 election.

DICK CHENEY: There has never been an individual who was a greater threat to our republic than Donald Trump.

JOHN YANG: When Trump ran for president again in 2024, Cheney, a lifelong Republican, cast his final vote for another member of the vice president's club, Democrat Kamala Harris.

He said citizens have a duty to put country above partisanship.

Once one of the most powerful Republican voices, Cheney was ostracized within the party and dismissed by Trump as an irrelevant RINO, a Republican in name only.

While he was vice president, Cheney's health had deteriorated.

In 2010, he suffered sudden cardiac arrest, an episode his cardiologist said likely would have killed him if not for an implanted defibrillator.

After a 20-month wait for a suitable donor, Cheney had a heart transplant.

It restored his health and allowed him to spend time with his grandchildren and return to two favorite pastimes, fly-fishing and hunting.

Before the transplant, Cheney underwent a nine-hour surgery.

Coming out of sedation, he recalled a dream.

DICK CHENEY: I had very vivid memories of being in Italy in a little village north of Rome, living in a nice villa.

And the family asked me afterwards: "Dad, were we with you?"

And I said: "No."

That wasn't the right answer.

But I was at peace.

JOHN YANG: At peace also describes Cheney's feelings about the controversies that make up so much of his legacy.

For the PBS "News Hour," I'm John Yang.