Supporters reach for GOP presidential candidate Donald Trump as he greets the crowd after a campaign event at Griffiss International Airport in Rome, N.Y., on Tuesday. (Jabin Botsford/The Washington Post)

Donald Trump built his business empire by exploiting the rules of business to his favor with brash skill, working corporate bankruptcy regulations, eminent-domain laws and the tax code to suit his bottom line.

But now Trump finds himself struggling to cope with a different set of rules — those governing the GOP nominating contest, which he and his campaign have failed to control with the same deftness he brags about as an entrepreneur. Instead, Trump has been disorganized and repeatedly outmaneuvered by rival Ted Cruz in locking up delegates in contested states.

Trump has responded by lashing out at party leaders, at his rivals and at the delegate process, arguing that the system is “totally corrupt” and that Cruz is “stealing” delegates at state conventions.

“These are dirty tricksters. This is a dirty trick. And I’ll tell you what, the RNC, the Republican National Committee, they should be ashamed of themselves for allowing this crap to happen,” Trump said during a rally here Tuesday.

Where Trump sees a conspiracy to keep him from the nomination, party leaders and Cruz see someone who failed to learn the rules of the game.

Republican front-runner Donald Trump railed against the GOP delegate selection process at a rally on April 12 in Rome, N.Y. (Reuters)

“Donald has been yelling and screaming, a lot of whining. I’m sure some cursing. And some late-night fevered tweeting. All the characteristics, I would note, we would want of a commander in chief,” the senator from Texas said this week in Irvine, Calif. “And the latest thing he seized upon is when people vote against him, they’re stealing the election.”

The Republican National Committee has leapt to defend the process, saying the delegate system has been used by the party to choose a presidential candidate for generations. Party leaders — who have sought to maintain a cordial relationship with Trump — also have made unusually pointed statements about the rules.

“It’s no secret how the delegates are allocated. It’s wide open for everyone to look at,” Sean Spicer, the RNC’s communications director, said on Fox News. “So not understanding that is one thing, but it’s hardly rigged when it’s done right out in the open.”

Trump’s campaign has struggled to compete in the ­delegate-by-delegate battle that has come to define the latest phase of the Republican nominating fight, exposing crucial organizational weaknesses in the front-runner’s campaign.

In a tacit acknowledgment of strategic shortfalls, Trump last week installed veteran GOP strategist Paul Manafort as his new “convention manager,” entrusted with shoring up his team’s efforts. On Tuesday, the campaign also announced it had hired another veteran GOP strategist, Tim Clark, to direct the campaign’s efforts in delegate-rich California.

Trump’s recriminations over the delegate system come with a dose of irony. His reputation as a savvy businessman grew out of his willingness — and aptitude — for testing the limits of the rules to get ahead. One famous example came in 1991, when Trump Taj Mahal in Atlantic City filed for bankruptcy protection.

A supporter holds up a sign as Republican presidential candidate Donald Trump speaks during a campaign event at the Times Union Center in Albany, N.Y., on Monday. (Jabin Botsford/The Washington Post)

He later boasted that the deal made him money, though it came at the expense of lenders. Justifying such decisions, Trump has said on several occasions that he used “the laws of the country to my benefit.” He has also leaned on eminent-domain laws and has proudly claimed that he uses tax experts to keep his payments low.

“I pay as little as possible. I use every single thing in the book. And I have great people,” Trump told Iowa voters in January. “It’s an expense, right? That’s the American way. I mean, do you want stupid people?”

But presidential politics is still a new game for Trump, and the task facing the campaign is enormous.

Each of the 56 states and territories has its own rules for allocating delegates to the Republican national convention in July, a complex system requiring intense planning and expertise to navigate. Trump’s rivals hope to keep him from crossing the necessary 1,237-delegate threshold required to secure the nomination outright before the convention. After the first round of voting at the convention, many delegates become “unbound” and can vote for whomever they like, regardless of their states’ preferences.

Anti-Trump conservatives have gleefully watched as the Trump campaign has struggled to grasp the delicate delegate-allocation process in states throughout the country.

“If your team ignores the rules and the criteria, then you have no one to blame but yourself,” said Katie Packer, who leads Our Principles, an anti-Trump PAC. “In fact, you deserve to lose.”

An embarrassing delegate shortfall over the weekend in Colorado, which did not hold a caucus or a primary, sent Trump into a days-long fury after Cruz lapped up all 34 available delegates. Trump roared his displeasure at campaign rallies across New York state this week and on Twitter.

“The people of Colorado had their vote taken away from them by the phony politicians. Biggest story in politics. This will not be allowed!” Trump tweeted Monday to his nearly 7.6 million followers.

Colorado officials have defended their delegate-allocation system, explaining that the rules have not changed since 2012. An aide in the Colorado Republican Party said that the primary was scrapped about 14 years ago and that the state party would like to see it reinstated.

Steve Hofman, a Colorado GOP delegate for Cruz, rejected the idea that anything illicit or un­ethical happened.

“The whole idea that there were tactics? I mean . . . it was Political Organization 101,” Hofman said. “Any notion that there was anything beyond saying how can we legitimately win these votes, that it was anything beyond that, it’s just a completely made-up assertion.”

Even some Trump supporters acknowledge that the billionaire has to play by the rules that have been in place.

Bill Hoogeveen, 58, of Saratoga, N.Y., said that he believes a contested convention in which Trump does not receive the nomination would result in “millions of people who leave the Republican Party.” But he also added that even if the rules governing the GOP nominating contest are fundamentally unfair, they have been in place from the beginning.

“I think the rules have already been set, so they have to play by the rules. It’s the game,” he said. “He’ll do it. He’s a smart guy.”

Ed O’Keefe in Washington contributed to this report.