Donald Trump used his first campaign rally in western New York to attack Sen. Ted Cruz for something the Texan happily boasts about: mastering party rules to elect his delegate slates to the Republican National Convention.

“They’re trying to subvert the movement,” Trump said to thousands of voters crammed into a frigid airplane hangar Sunday. “They can’t do it with bodies, so they’re trying to subvert the movement with crooked shenanigans.”

The Rochester rally was only Trump’s second in the 14-day New York campaign, and his first since Cruz swept Colorado’s 34 available delegates in a series of conventions. Trump’s hastily assembled delegate-chasing operation, which had been optimistic about the state, bumbled through a series of votes and came out empty there.

In an interview Sunday morning on “Meet the Press,” Trump’s newly promoted convention manager, Paul Manafort, accused Cruz of “Gestapo tactics.” The Cruz campaign, which describes its convention wins as proof of momentum, responded with mockery.

“It’s no surprise that Trump’s team will lash out with falsehoods to distract from their failure,” said Cruz communications director Alice Stewart. “We have earned our success by working hard to build a superior organization.”

A man holds a cutout of U.S. Republican presidential candidate Donald Trump as Trump speaks during a campaign event at an airplane hanger in Rochester, N.Y. Sunday. (Carlo Allegri/Reuters)

In Rochester, Trump’s supporters were seething about the possibility of Trump falling short on delegates and losing the nomination at a “brokered convention” — a term that drew loud, angry boos when Trump’s state co-chairman, Carl Paladino, used it.

“They suggest they can take that right away from the American people to choose their leader,” Paladino said. “How brazen is that? How can someone become so out of touch with the reality of America, the reality that this country has the rule of law?”

Trump’s supporters alternately said that their candidate would win outright, or that a Trump loss at the convention would destroy their faith in the Republican Party.

“If they do that [to] Donald, he’ll probably run third party, and I’ll vote for him,” said Mike Rankin, a 67-year old heating and cooling technician.

When he took the stage, Trump recited numbers of job losses in Rochester, naming individual companies that he would “hit with a 35 percent tax” until they agreed to return and create jobs.

“I will bring it back so fast,” he promised. “Your head will spin.”

Trump seemed to take particular joy in a Boston Globe editorial that took the form of a satirical front page from the first year of a hypothetical — and disastrous — Trump presidency. The mock page’s banner headline read ­“DEPORTATIONS TO BEGIN.”

“They sold it for $1 and now they run editorials telling me what I should be doing,” he said.

Trump also talked the audience through his victories over “Lyin’ Ted,” an insulting sobriquet that has quickly become a chant. Skipping over Colorado, Trump asked his voters whether it was fair that a candidate who has received “millions more votes than Cruz” to be deprived of victory. The total before New York’s April 19 primary, which Trump is heavily favored to win, is about 8.2 million for Trump to 6.3 million for Cruz, in caucuses and primaries.

“I go to Louisiana, I win Louisiana,” said Trump. “Then I find out I get less delegates than Cruz because of some nonsense. I say this to the RNC, and I say it to the Republican Party: You’re going to have a big problem, folks, because the people don’t like what’s going on.”

Trump declared a kind of solidarity with Sen. Bernie Sanders (Vt.), a Democratic presidential candidate he “couldn’t care less about,” over the lack of respect they seemed to get for winning states.

“He wins and wins and wins, and I hear he doesn’t have a chance?” asked Trump. “This is a crooked system, folks. I couldn’t care less, but he wins, like me. I’ve won twice as much, millions more votes. People who have never voted have come out and voted for Trump. The Republicans are up 70 percent; the Democrats are down 30 percent from four years ago. Every one of those people, if they try to do their little shenanigans, which is politics as usual, every one of those people . . .”

Trump, who occasionally and vaguely threatens not to support the party’s nominee if he loses and is not “respected,” then veered off. He bragged about his supporters but implied that they would stay home if he did not win the GOP nomination.

Public polling suggests that New York would be an imperfect test case for Trump’s theory. In a Quinnipiac University poll released March 31, both Trump and Cruz lost a hypothetical Empire State election to any Democrat. Former secretary of state Hillary Clinton led Trump by 20 points and Cruz by 21 points; the Brooklyn-born Sanders won each matchup, by 24 and 28 points, respectively.

But in Rochester, Trump’s supporters said that they disbelieved the polls, and that the swarms around them proved that he could win. Trump’s swagger returned as soon as he finished discussing the finer points of delegate selection.

“I think we should win before the convention,” Trump said. “I’ve been winning with evangelicals, which is incredible. They don’t like liars.”

Katie Zezima in Washington contributed to this report.