(CNN) Former GOP presidential nominee Mitt Romney is again warning his party of the dangers of a Donald Trump nomination, saying a three-man race likely paves the way for the New York billionaire to capture the nomination on the first ballot of this summer's GOP convention in Cleveland.

"If (Gov. John Kasich and Sen. Ted Cruz) are both going at it aggressively until the very end then I think Trump gets it on the first ballot," Romney said.

Both Cruz and Kasich trail Trump badly in the delegate count, but only Cruz has a mathematical shot of catching Trump. The Texas senator's campaign has also proven far more effective in organizing delegates who would be likely to support him in Cleveland in the event of a contested convention.

Romney argues that even if Trump were to fail to reach the magic number of 1,237 delegates needed to capture the nomination going into Cleveland, he could still wrangle the votes by wooing delegates.

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