Some conservative movement leaders are reportedly abandoning the GOP, concerned the populism and incendiary tone of presumptive nominee Donald Trump represents the party's "loss of purpose.""It’s a crisis," Al Cardenas, a former chairman of the American Conservative Union, who is withholding support for Trump, tells the"If we do away with the fundamental strength of the conservative movement, which is our ideas and values and principles, then you don’t have anything left but politics. A movement can survive the loss of an election cycle, but it can’t survive the loss of its purpose, and that’s what we’re battling here."Conservative commentator Erick Erickson — who is among those urging an independent candidate — tells the Post a move by conservatives away from the GOP is a good thing."One of the silver linings that can come from this is that the conservative movement as an entity pulls back away from the Republican Party," he tells the Post. "During the Bush administration, it became a subsidiary of the Republican Party. This gives us a good opportunity as conservatives to stand on our own two feet."The "big question" is whetherof House Speaker Paul Ryan's conservative agenda is "an aberration in policy" or a GOP "policy shift," according to Lanhee Chen of Stanford University's Hoover Institution."The Ryan agenda isn’t just about Paul Ryan, but it’s what conservatives have agreed on as the best way forward — and Trump is deviating from that in so many ways," Chen tells the Post."The big question really is, to what extent is the Trump phenomenon an aberration in policy versus some more fundamental shift? I tend to think of it as an aberration."Particularly anxious are conservatives who worry Trump would weaken the party’s moral tilt, the Post reports."I haven’t heard him frame things in moral terms,” Iowa GOP Rep. Steve King tells the Post."I don’t hear him speak about the Constitution. It’s hard to believe he has any sort of deep conviction on life and marriage. I don’t see him being guided by constitutional principles. He doesn’t speak about them, ever. That’s what’s troubling everyone. He’s not even speaking in the same language, politically, that we speak.""We run the risk of the underpinnings of our convictions being disregarded," he tells the Post.