The author repeatedly writes "conservatism and the Republican Party†or "conservatives and Republicans" as if they are inseparable or the same thing. They are not.
There are conservative Republicans but Republicans in general are not conservatives especially Republican politicians.
Almost all Republicans politician are Leftist. And only less so than the Democrats by a small degree.
Republican politicians much like the Democrats like to grow government. They sell influence to those who wish to grow government in a way that benefits them. And like Democrats they are loath to kill a useless or even destructive program.
I am a conservative and a Republican but I am only a Republican because I know that conservatives must capture and change the Republican Party from within just as the Communist captured and changed the Democrat Party from within.
I however believe that it will take conservatives much longer to change the Republican Party in to a freedom loving conservative party than it did the communist to change the Democrat Party. Inertia favored the communist and still does.
I think Prager says “conservatives and Republicans” precisely because he does know the difference, though I doubt he would consider most Republicans “leftists”. I don’t think they are either. Nor do most leftists. Neither are they conservatives. In fact they don’t really care about ideology. They say conservative sounding things to get elected, but don’t actually care about them. They care about money and power, not ideology.
PS. The left on the other hand cares about money, power and ideology.