Five states are holding primaries on Tuesday: Connecticut, Maryland, Delaware, Rhode Island and Pennsylvania. Hillary Clinton and Donald Trump could win every state, making it that much harder for Ted Cruz, John Kasich and Bernie Sanders to slow their momentum. Clinton and Trump can't clinch the nominations on Tuesday, but the results will help shape the rest of the primaries.
Can Trump and Clinton sweep?
Trump and Clinton could win all five states holding primaries on Tuesday. Both candidates are leading in polls and entered the day with momentum after commanding victories in New York last week. If Trump and Clinton prevail in every contest, that would deal their opponents a huge blow.
On the Democratic side, a Clinton sweep would not give her enough delegates to clinch the party's nomination. But it would effectively end her primary battle with Sanders, even if Sanders does not immediately drop out of the race.
The same is true for Trump. He can't clinch the nomination on Tuesday, even if he wins all five primaries — he would need to win several big states, including Indiana and California, to get to 1,237 delegates. Still, a sweep would give Trump a big boost heading into the Indiana primary on May 3.
For GOP, small states like Delaware matter
Smaller, left-leaning states like Delaware and Maryland usually don't have much of an impact on the Republican presidential primaries. But this year Donald Trump needs every delegate he can get to reach 1,237 by the end of the primaries and clinch the nomination. So the GOP primaries in Delaware (which has 16 delegates) and Maryland (38 delegates) suddenly matter.
Entering Tuesday, Trump was leading in the polls in both states. Maryland awards its delegates on a winner-take-all basis by statewide and congressional district results. Trump could lose a few delegates if Cruz wins the congressional districts surrounding Washington, D.C. But he is expected to perform well across the rest of the state, so Trump could come away with the vast majority of Maryland's delegates.
Delaware's delegates are winner-take-all. Trump had a 37-point lead over Kasich and a 40-point lead over Cruz in a statewide poll released last week. Trump is expected to win all of Delaware's delegates, and he could add to his delegate lead with victories on Tuesday in Connecticut and Rhode Island — another pair of small, liberal states that are playing an unusually big role in the GOP primaries.
Pennsylvania preview
If Trump wins the Republican nomination, he'll need to carry key swing states like Pennsylvania in the general election in order to have a shot at winning the presidency. So while the state's GOP primary is closed — meaning that independents and Democrats can't participate — it can still provide some important clues as to how Trump would fare in Pennsylvania in November.
If Trump does better than expected with women and younger voters, that would show that he could potentially build a broad-enough coalition of Republicans to compete in Pennsylvania in the fall. But if Trump can't expand his base in the state on Tuesday, that could spell trouble for him down the line.
Another thing to watch for is turnout. So far, turnout in the GOP primaries is significantly higher than it was in 2012. There are several reasons why, but there's no doubt that Trump has helped drive enthusiasm on the Republican side this cycle. If Trump wins the party's nomination, he'll likely need high turnout in states like Pennsylvania to win the general election. Tuesday's numbers will give us a preview of his level of support in the state.
Delegate battle in Pa.
In addition to voting for a presidential candidate, Pennsylvania voters on Tuesday will also elect 54 unbound delegates to the Republican National Convention this summer. The delegates can back whomever they want at the convention, and they weren't required to commit to a candidate before today's vote. That makes them sought-after free agents in a primary battle that could be decided at the RNC in Cleveland, if Trump fails to clinch the nomination before then.
The slate of Pennsylvania delegates is almost as important as the statewide vote. Campaigns will be following the results of the delegate elections very closely to see if their supporters make the final cut.
Will Sanders make a change?
If Sanders doesn't win a single state on Tuesday, he'll face increased pressure from Democrats to scale back his attacks on Clinton — or drop out of the race altogether. How Sanders adapts to that pressure will help set the tone for the remainder of the Democratic primaries.
Sanders has two choices (assuming he stays in the race, which he has promised to do). He can continue attacking Clinton, and risk angering party leaders who are eager to start organizing for Clinton's general election campaign. Or Sanders can start sending signals to his base that they need to rally around Clinton in order to beat the eventual GOP nominee. Based on his strategy in the primaries so far, it's unlikely that Sanders will make any big changes.