Who would you consider a valid conservative if not the most mainstream conservative news organization? I have the utmost respect for David Frum and a lot of the "Never Trump" type conservatives who clearly actually believed in their principled ideas, but even they would tell you that they're a minority of a minority. It's often hard to tell if Fox News is leading or following mainstream conservative opinion (and of course it's never that simple), but clearly they track the majority opinions of people who consider themselves conservative.