The rationale:

I don't want to see another Republican President any more than the next Democrat. But I do want to see a Republican nominee who stands up for civil rights, who speaks sensibly about America's place in the world, who insists on the rule of law and rejects the exceptionalism and emergency powers advocated by every other GOP candidate. I want to see the Republican party rally around a voice that is not encouraging them to tear apart the Constitution in fear of terrorism. I want to see a Republican nominee who will enable the American people to experience a campaign of hope and ideas, not of fear and McCarthyism.