Republican National Committee head Reince Priebus declared Sunday the anti-Donald Trump Republicans' effort to launch a third-party bid for the White House is a "suicide mission."In an interview with CBS News'Priebus — days after a— warns against a third-party attempt at "blowing everything up.""It's a suicide mission because you're not only changing and throwing out eight years of the White House" but also jeopardizing the course of the Supreme Court, he replied."We could have up to three justices change over in the next eight years. And this is a suicide mission, it is not right," he declared. "And I think what people should do is take the [House Speaker] Paul Ryan approach to work with Donald Trump and find out whether or not there's common ground and whether there can be assurances on the Supreme Court… to make sure that our future is secure down the line as opposed to blowing everything up."On their high-profile meeting last Thursday, Priebus maintained Ryan and Trump "agree on far more than they disagree.""They agree on various agenda items," he said. "Paul Ryan's agenda, agree on the Supreme Court. They agree on the platform of the Republican Party. They agree on abortion. I think you've got about 80 percent overlap."