WASHINGTON — (CNN) Donald Trump and Hillary Clinton are poised to take big steps toward their party’s presidential nominations as voters in five northeastern states head to the polls Tuesday.

Voters in Connecticut, Delaware, Maryland, Pennsylvania and Rhode Island will cast their ballots with hundreds of delegates at stake.

Clinton and Trump are hoping to sweep the contests, which would severely complicate the already daunting electoral math facing their challengers.

For Trump, fresh off his thumping win last week in New York, dominating the “Acela primaries” would underscore his argument that he is the only viable Republican candidate. The Acela nickname comes from the high speed Amtrak train that spans the northeast corridor.

Clinton, meanwhile, still basking in her own commanding victory in New York, is targeting big wins to bolster her contention that, despite his energetic challenge, Vermont Sen. Bernie Sanders cannot overtake her and deprive her of the Democratic nomination.

The primaries are taking place after an already volatile presidential race was rocked anew by a deal between Republicans Ted Cruz and John Kasich to divide up three primary races in the coming weeks in a bid to halt Trump short of the 1,237 delegates he needs for the nomination.

The billionaire has blasted the deal as “collusion” and complained it is another sign the establishment is trying to deprive him of the nomination that is rightfully his — a position that would be further validated by big victories on Tuesday.

The Cruz-Kasich pact does not apply Tuesday, however, and the Ohio governor is hoping his moderate brand of conservatism will appeal to voters in the five states and that he will be able to pile up a respectable collection of delegates.

The region is not likely to be hospitable ground for the more ideological Cruz, whose claim to being a genuine rival to Trump took a battering with his poor showing in New York and could be further called into question on Tuesday.

Republicans are battling for 172 delegates on Tuesday, and Trump goes into the night needing to win 58% of delegates available in remaining primaries to capture the nomination, according to CNN estimates.

The always complicated science of delegate allocation will be even more arcane than usual because of Pennsylvania’s one-of-a-kind system, where 54 of the state’s 71 delegates are unbound.

That means they can vote for who they like in the first round of voting in the Republican convention in Cleveland in July and will be a key voting bloc if Trump doesn’t win 1,237 delegates.

In the event that Trump falls short of that magic number, unbound delegates could be crucial in deciding the fate of the Republican nomination.

Cruz has mounted an especially sophisticated operation to fill delegate slates with sympathetic activists who could desert Trump in later rounds of voting in Cleveland should the billionaire fall short on the first ballot.

In the Democratic race, Clinton is banking on a big night to build on her resounding success in New York, which stunted Sanders’ momentum and left the Vermont senator — for all his fundraising muscle and large rallies — fending off calls from Clinton supporters to fold his campaign so that she can start exclusively targeting Republicans.

Clinton did not even mention Sanders during the final rally of her Pennsylvania campaign in Philadelphia on Monday night — instead taking aim at Trump’s rhetoric.

She said it was important for voters to “send a really strong message here in Pennsylvania that we’re not going to be intimidated or deterred by the demagoguery.”

Sanders and Clinton are competing for 384 pledged delegates on Tuesday. Clinton currently leads Sanders by 253 pledged delegates, according to a CNN estimate, and is dominating the count among superdelegates — party officials and activists who also have a convention vote.

Since the Democratic primary race is decided by proportionally allocated delegates, Clinton is unlikely to reach the 2,383 delegates need to clinch the nomination until future states vote.

But that system also means that without lopsided primary wins, it is impossible for Sanders to catch her.

As it is, Sanders would have to win 82% of remaining delegates available to capture the nomination.

The former secretary of state is hoping that large turnout among African American voters, which have underpinned her primary campaign, will help her cruise to victories in states like Pennsylvania, Connecticut and Maryland.

She has also been emphasizing her family heritage in Pennsylvania.

Sanders best hopes of a win appear to lie in Rhode Island, which is the only state up for grabs Tuesday that allows independents to vote in the Democratic contest.

But to swing the narrative of the 2016 race, Sanders desperately needs to spring a surprise on Tuesday, possibly by pulling off a come from behind victory in Pennsylvania, the biggest state on offer with 189 delegates, to restore momentum he lost in New York. But Clinton led by 13 points in a Monmouth University poll of the state last week.

Without a victory, Sanders’ case that he will be able to flip Democratic super delegates at the convention in Philadelphia in July away from Clinton begins to look increasingly thin.

And even if he did win Pennsylvania, Clinton’s large lead in Maryland, the second largest state up for grabs on Tuesday — she led 57% to 32% in a recent Monmouth poll — could help her stretch her delegate lead anyway.

Still, Sanders is adamant that he will fight to the finish of the campaign — including the California primary on June 7.

“It’s a narrow path, but we do have a path,” Sanders told CNN’s Chris Cuomo on “New Day” Tuesday. “And the idea that we should not contest in California — our largest state, let the people of California determine what the agenda of the Democratic Party is and who the candidate for president should be — is pretty crazy.”