Insisting that the delegate selection process is “corrupt and crooked,” Donald J. Trump offered a vivid example on Sunday to prove his point.
Imagine being wooed by Mr. Trump.
“Look, nobody has better toys than I do,” he told reporters at a hotel on Staten Island, where he pressed his case that the system was rigged against him. “I can put them in the best planes and bring them to the best resorts anywhere in the world.”
But Mr. Trump said that was unseemly.
“You’re basically buying these people,” he added. “You’re basically saying, ‘Delegate, listen, we’re going to send you to Mar-a-Lago on a Boeing 757, you’re going to use the spa, you’re going to this, you’re going to that, we want your vote.’ That’s a corrupt system.”
Mr. Trump’s comments were the latest salvo in an escalating war against the Republican National Committee over how delegates were being selected in the presidential race.
Two days before New York’s primaries, Mr. Trump was the only Republican presidential candidate to campaign in the state, where polls showed him with a wide lead.
During his visit to Staten Island, a stronghold of his support, he accepted an award from the New York Veteran Police Association and spoke at a party brunch. At a rally later in Poughkeepsie, he berated party officials once again.
Still, speaking to reporters on Staten Island, Mr. Trump said he hoped that the July convention “doesn’t involve violence.”
“And I don’t think it will,” he said. “But I will say this: It’s a rigged system. It’s a crooked system. It’s 100 percent crooked.”
Polls have shown Mrs. Clinton with an edge over Mr. Sanders, but Mr. Sanders is hoping for an unexpectedly strong performance that would embarrass Mrs. Clinton on her adopted turf.
Both candidates were knocked off balance on Sunday when questioned about an issue with particular relevance in New York: a bill that would allow foreign governments to be held responsible in American courts for having a role in terrorist attacks, such as the Sept. 11 attacks.
The New York Times reported on Friday that Saudi Arabia had told the Obama administration and members of Congress that it would sell off hundreds of billions of dollars’ worth of American assets held by the kingdom if Congress passed the bill. The Obama administration has lobbied Congress to block the bill’s passage, The Times reported.
In television interviews, Mr. Sanders and Mrs. Clinton said they needed more information before they could say where they stood on the bill.
But after Mrs. Clinton’s TV appearance, her campaign quickly released a statement breaking with the Obama administration over the issue. The statement said Mrs. Clinton supported efforts “to secure the ability of 9/11 families and other victims of terrorist acts to hold accountable those responsible.”
Later in the day, Mr. Sanders’s campaign also issued a statement in support of the legislation.
In Mount Vernon on Sunday, Mrs. Clinton spoke at a Baptist church, saying she was the candidate most willing to take stands in favor of gun control. In Upper Manhattan, she danced at a block party in Washington Heights.
At a block party in the Bedford-Stuyvesant section of Brooklyn, Mayor Bill de Blasio urged New Yorkers to help turn out votes for her. Mrs. Clinton greeted him with a hug and a kiss on the cheek.
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“Anybody see the debate?” she asked, addressing the crowd from the bed of a Ford pickup truck and referring to the Democratic debate in Brooklyn on Thursday. “We talked about the greed and recklessness of Wall Street. I take a back seat to no one in taking them on.”
After hosting packed rallies around New York State, Mr. Sanders turned his attention to courting black voters in New York City on Sunday, visiting a predominantly black church in Harlem and a Brownsville housing project.
Mr. Sanders also had a rally in Prospect Park in Brooklyn, which his campaign said drew 28,000 people, the largest crowd of his presidential bid.
In Brownsville, Mr. Sanders took a tour of the Howard Houses along with some local elected officials, and his campaign released a plan for affordable housing.
“This is the wealthiest country in the history of the world,” Mr. Sanders said. “People should not be forced to live in dilapidated housing.”
As Mr. Sanders walked across the complex, several residents happily shouted at him. But others pointedly criticized him for using the apartments for what they viewed as a photo opportunity.
Anthony Portis, a 34-year-old construction worker, called the senator’s visit “a political stunt to gain all the black votes in the neighborhood.”
“This area always feels like we are left out,” he said.
Mr. Sanders said that he understood that some would be apprehensive about his visit but that he wanted to call attention to the issues faced by people in housing projects.
“Believe me, I can understand the cynicism,” he said. “But my understanding is that not too many presidential candidates have come to Brownsville housing projects.”