Senate Majority Leader Mitch McConnell Declines to Say If Trump Is Qualified to Be POTUS "That will be up to the American people to decide," McConnell said.

 -- Republican Senate Majority Leader Mitch McConnell declined Sunday to say if Donald Trump, his party's presumptive presidential candidate, is qualified to be president.

"Well, look, I think it's no question that he's made a number of mistakes over the last few weeks. I think they're beginning to right the ship. It's a long time until November. And the burden obviously will be on him to convince people that he can handle this job," McConnell said on ABC's "This Week."

Pressed by ABC Chief Anchor George Stephanopoulos on whether he thinks Trump is qualified, McConnell replied, "I leave it up to the American people to decide."

A new ABC News/Washington Post poll released today shows 64 percent of Americans, a new high, say Trump is unqualified to serve as president.

That could spell trouble for the presumptive Republican nominee in November, but the Majority Leader insists Trump won the Republican nomination fairly and that Republican primary voters have made their decision.

"He won the Republican nomination fair and square," McConnell said. "He got more votes than anybody else, against a whole lot of well-qualified candidates, and so our primary voters have made their decision as to who they want to be the nominee," he said. "The American people will be able to make that decision in the fall."

Conservative commentator and columnist George Will said Friday that he's leaving the Republican Party because of Donald Trump, and he urged other conservatives to do the same.

McConnell offered reassurance to Will, whom he called a friend: "The Republican Party is still going to be America's conservative party," McConnell told Stephanopoulos, adding that the party's platform will include basic principles Republicans believe in.

That means that proposals Trump has been touting throughout his campaign will not be included in the platform, including his proposed ban on Muslims entering the country.

"Our nominee may not agree with every single one of those, but the Republican Party, it will remain America's conservative party," he said. "The platform will be a traditional Republican platform...and I don't expect it to differ that much from the platform we had four years ago.