Donald Trump is poised to extend his lead in the Republican presidential race in a string of East Coast primaries on Tuesday, but a complicated contest in Pennsylvania, the day's biggest prize, will test his recently reorganized campaign.
The state features the sort of complex rules that Trump has repeatedly slammed for being "rigged" and that forced him this month to reshuffle his team to better compete with main rival Ted Cruz for the 1,237 delegates needed to win the nomination for the Nov. 8 election.
"It's as crooked almost as Hillary Clinton," Trump said on Monday at a campaign event in West Chester, Pennsylvania, in an attack on both the Republican primary rules and the Democratic presidential front-runner.
Just 17 of the 71 Republican delegates up for grabs in Pennsylvania on Tuesday are allocated to the candidate who wins its primary. The rest – people who are elected directly by voters – are free agents, able to support anyone they choose at the Republican National Convention in July.
Pennsylvania and other states holding primaries on Tuesday – Maryland, Delaware, Rhode Island and Connecticut – are favorable terrain for Trump. Opinion polls show him leading in all five, prompting Cruz and John Kasich, the third Republican in the race, to announce an anti-Trump alliance.
On the Democratic side, Clinton also looks set to solidify her lead over U.S. Sen. Bernie Sanders in Tuesday's contests.
But Sanders, who has attacked Clinton from the left with pledges to do more than she would to address social inequality, insisted he stood a good chance to win some of the states. "I think we've got a path to victory and we're going to fight this until the last vote is cast," Sanders said on CNN.
Before polls opened, Trump continued battering the Republican delegate allocation system as rigged. "The whole delegate system is a sham," he said on Fox News. The real estate magnate has lost the battle for delegates in some states where he won the popular vote.
On April 7, he announced he was reorganizing his campaign to focus on delegate and convention strategy, hiring advisers with convention experience, while railing against the Republican system.
In Pennsylvania, candidates hope to get as many die-hard supporters as possible elected as delegates, both to build support on the first ballot and to bolster their position if no one gets to 1,237 delegates outright and the Cleveland convention becomes a protracted fight for the nomination.
It is unclear if Trump's campaign revved up its efforts in time to make a difference in Pennsylvania's delegate race.
U.S. Rep. Lou Barletta of Pennsylvania, a Trump surrogate, said the campaign had taken some steps, including printing cards naming its preferred candidates for delegates so that voters going to the polls would know who backs Trump.
Before that, "we were just scribbling names on a piece of paper for them," Barletta said. "I think the organization coming here to Pennsylvania was just in the nick of time."
Cruz's Pennsylvania chairman, Lowman Henry, said he had not noticed a ramp-up by Trump there. "All we've noticed is a bunch of whining about it," he said. "Our response is: They whine, we win."
Cruz, a U.S. senator from Texas, has met with would-be delegates who have promised to support him if they are elected, as well as candidates who have not declared any allegiance, Henry said. Kasich, the Ohio governor, has also met with prospective delegates.
Gabriel Keller, a Pittsburgh-area Trump supporter, said the New York billionaire's campaign had proven unreliable.
He said Trump's operation asked him in December to run to be a delegate but that communication then stopped. Some Trump backers in the state got help getting on the ballot in their congressional districts, but Keller said he did not. When the Trump campaign posted its slate of recommended delegates on its website, he said his name was not on it.
It is difficult to predict which presidential candidate will get the most support from Pennsylvania. Many delegate candidates have said they will vote for whoever wins the state or their district, at least on the first ballot at the convention.
If those delegates hold to their informal promises, Trump could win most of Pennsylvania's votes on the first round in Cleveland, said Charles Gerow, a conservative strategist also running to be a Pennsylvania delegate.
But if Trump falls short of the votes needed to win on the first ballot in Cleveland, and delegates across the country begin switching sides, the efforts now being made to woo Pennsylvania delegates could pay off.