WASHINGTON (Reuters) - A senior adviser to Republican presidential candidate Ted Cruz on Sunday accused rival Donald Trump's campaign of taking a "banana republic approach" by complaining that party rules for selecting a nominee are rigged against him.
Former Virginia Attorney General Ken Cuccinelli, the Texas senator's delegate operations manager, said on ABC's "This Week" that the Trump campaign is challenging the delegate selection process "because they're getting beat on the ground."
Cuccinelli and Trump's campaign manager, Corey Lewandowski, as well as the third Republican candidate, Ohio Governor John Kasich, traded punches over the delegate selection process on Sunday news shows.
Trump remains the front-runner in the race to be the Republican Party's candidate in November's general election. But it remains unclear whether the billionaire businessman will arrive at the party's July 18-21 convention in Cleveland with the 1,237-delegate majority needed to clinch the nomination on the first ballot.
The next big face-off is New York state's primary on Tuesday, with 95 delegates at stake.
Opinion polls show Trump, a New Yorker, well ahead of his rivals, with Kasich and Cruz trailing behind. The latest CBS News poll, released on Sunday, show Trump supported by 49 percent of those surveyed, followed by 31 percent for Cruz and 16 percent for Kasich.
In recent days, Trump has become increasingly agitated as the Cruz campaign outmaneuvers him in the complex art of securing delegates that are not simply allocated by a popular vote. The party rules for picking delegates vary by state.
Cuccinelli said Cruz has been "winning elections. And when we win, Trump whines."
"This is a banana republic approach from the Trump team," he said. "... They have a media campaign. But Ted Cruz has built a grassroots campaign ..."
On "Fox News Sunday," Trump's Lewandowski pointed to Florida, where the candidate won the primary in a landslide. But Trump can count on the support of only 69 of the state's 99 delegates because the state Republican Party chairman is allowed to appoint 30.
Said Lewandowski, "Ted Cruz does well in places where party bosses get to set those rules and people don't get to go and vote."
Another senior Trump adviser, delegate selection specialist Paul Manafort, told ABC the campaign will protest results in Missouri and Colorado.
But in several interviews on Sunday, Republican National Committee Chairman Reince Priebus again denied that the delegate selection rules are rigged against Trump.
Kasich ridiculed Trump and his campaign for suggesting the delegate selection rules are fixed and that a "dirty trick" allowed Cruz to win Colorado's nominating contest without a statewide vote.
Kasich, interviewed by CNN, said Trump should "act like you're a professional. Be a pro."
The governor is staking his bid on a contested convention in which he would seek to be elected the nominee on the second ballot or subsequent vote by convention delegates.
Kasich said he would prevail as the party's nominee, because he has "a message that appeals to blue-collar conservative Democrats and independents."
(Reporting by Diane Bartz, Lisa Lambert and David Shepardson; Writing by David Shepardson; Editing by Jonathan Oatis)