House Speaker Paul Ryan Dismisses Idea of Convention Challenge to Donald Trump “The way I see it is he won the thing fair and square,” Ryan said.

 -- While some conservatives are still holding out hope that there is a way to block presumptive GOP nominee Donald Trump from securing the nomination at the Republican convention next month, House Speaker Paul Ryan isn’t one of them.

"The way I see it is he won the thing fair and square," Ryan told George Stephanopoulos in an interview airing on "This Week" Sunday.

"Seventeen people competed, one person won and he got the delegates," Ryan added. "The delegates ultimately decide these things, but he won fair and square."

Trump reached the magic number of 1,237 delegates needed to secure the GOP nomination at the end of May, damping down talk of a contested GOP convention in Cleveland.

But some Republicans, including Weekly Standard editor and ABC News contributor Bill Kristol, have not lost hope of recruiting a third party alternative to the billionaire businessman, or of using the rules of the convention to block Trump's nomination.

The house speaker endorsed Trump last week in an op-ed for The Janesville Gazette.

"I feel confident he would help us turn the ideas in this agenda into laws to help improve people’s lives. That's why I'll be voting for him this fall," Ryan wrote.

Since giving his endorsement to Trump, Ryan hasn't shied away from critiquing the presumptive GOP presidential nominee. The house speaker has privately and publicly spoken to Trump about his comments on federal Judge Gonzalo Curiel's ethnicity, telling Stephanopoulos that Trump's remarks were "beyond the pale."

See more of Speaker Paul Ryan’s interview Sunday morning on “This Week.”