A recent column by WaPo columnist Kathleen Parker speculated on what Donald Trump has over Republicans that they continue to be loyal to him. She speculated that he must have blackmail tapes on each of them.
Along the way she made the statement that "the purpose of conservatives is to put the brakes on liberals' excesses".
There are two ways you can put the brakes on something. You can stop it completely or you can slow it down. Either way, this says a lot about Parker's view of conservatives.
If she meant that conservatives are to slow liberals then she is conceding that the liberals are correct in everything but they are moving too fast.
If she meant that conservatives are to stop liberals without offering a direction of their own then she is echoing the Democrats' charge that the Republicans are the "party of No" with nothing to offer.
This is what happens to a conservative who starts appearing on Sunday talk shows and writing for the WaPo. They act as a token conservetive, coasting on credentials that are way past renewing while parroting the liberals. After a while they accept the values of the people who surround them and are reduced to calling for the same goals but at a slower pace. That pretty much describes all of the "conservatives" at the WaPo as well as the "conservatives" on Sunday talk shows (I'm looking at you, John Kasich).
And, to answer Parker's question, Trump doesn't "have" anything on the Republicans who support him. They support him because, to him, conservative values are more than just applying the brakes to a liberal agenda. A conservative agenda means putting American workers first, being skeptical about global warming, standing up to China, having trade policies that are as advantageous as possible for Americans, energy independence and policies that unite Americans instead of teaching that all whites are racists.
Sorry I don't have a link to Parker's column. I read it in dead tree format and didn't see a link when I googled.