“The Cruz campaign, even in the closed systems like Colorado, like Missouri, they’re not playing by their own rules,” Manafort charged, accusing Texas Sen. Ted Cruz’s campaign of having to “muscle things,” without being specific.

Manafort said protests needed to be filed soon, but he offered no timeline.

“If you’re so confident about getting to 1,237 [delegates] before Cleveland, then why does Mr. Trump complain about the rules?” host George Stephanopoulos asked.

Trump is “complaining about the system,” Manafort said. “That’s the point that keeps getting lost here. He’s saying we’re playing by the — we’re playing to open up the process. We’re trying to let voters decide, members of the Republican Party, independents, decide who the Republican nominee should be — not the party bosses. That’s the system of the 1920s, not 2016.”