By John Whitesides
WASHINGTON (Reuters) - Republican presidential front-runner Donald Trump lashed out at what he called the party's "rigged" delegate selection rules on Monday after rival Ted Cruz swept all of Colorado's 34 delegates during the weekend.
The New York billionaire, who leads in the Republican race for the national convention delegates who will select the party nominee in July, said the process, which varies state by state, was set up to benefit party insiders and shut out insurgent candidates.
"The system is rigged, it's crooked," Trump said on Fox News on Monday, alleging the Colorado convention results showed voters were being denied a voice in the process.
"There was no voting. I didn't go out there to make a speech or anything, there's no voting," Trump said. "The people out there are going crazy, in the Denver area and Colorado itself, and they're going absolutely crazy because they weren't given a vote. This was given by politicians - it's a crooked deal."
Cruz, a U.S. senator from Texas, has outmaneuvered Trump in Colorado and several other states in recent weeks in the battle for the 1,237 delegates needed to win the nomination on the first ballot and avoid a messy floor fight at the convention.
Trump has 743 bound delegates and Cruz has 545, according to an Associated Press count. But both are at risk of not acquiring enough delegates for a first-ballot victory, leaving many delegates free to switch their votes on later ballots.
The rules for choosing convention delegates vary by state and are coming under more intense scrutiny than usual because of the closeness of the Republican race.
Trump, who has brought in veteran strategist Paul Manafort to lead his delegate-acquisition efforts, complained about Cruz's recent success at local and state party meetings where activists select the actual delegates who will attend the national convention in July.
On Sunday, Manafort said the Cruz campaign was using "Gestapo tactics" to win over delegates while on Monday Trump accused Cruz of trying to steal delegates in South Carolina, where Trump won the state primary in February.
Cruz came in third in the South Carolina primary but won three delegates on Saturday at congressional district meetings, according to local media.
"YOU CAN BUY ALL THESE VOTES"
"Now they're trying to pick off those delegates one by one," Trump said. "That's not the way democracy is supposed to work. They offer them trips, they offer them all sorts of things and you're allowed to do that. You can buy all these votes."
The Cruz campaign did not immediately respond to requests for comment on Trump's statements but on Sunday spokeswoman Catherine Frazier said the allegations were "more sour grapes from Trump."
"We are winning because we've put in the hard work to build a superior organization," she told CNN.
The Colorado Republican Party also defended its delegate selection process, re-tweeting a post by commentator Ari Armstrong. "Claiming delegates were 'stolen' insults the Republicans who participated," Armstrong wrote.
Trump's organizational troubles even extend to two of his children. Eric Trump, 32, and Ivanka Trump, 34, missed the deadline for registering as Republicans to vote in next week's New York primary. State records show both are registered voters who are not enrolled in a party, ABC News reported.
For already registered voters, any request to switch party affiliation must have been made by early October. The deadline for new voter registrations was March 25.
Trump was the target on Monday of a new ad by the Democratic front-runner, Hillary Clinton, that listed Trump's comments on women, Mexican immigrants and Muslims.
Both Clinton and rival Bernie Sanders, a U.S. senator of Vermont, have tried to position themselves as the Democrat most capable of defeating Trump.
"Donald Trump says we can solve America's problems by turning against each other," Clinton's ad said. "It's wrong and it goes against everything New York and America stand for."
(Additional reporting by Doina Chiacu and Megan Cassella; Editing by Bill Trott)