Ronald Reagan was elected by the people to a finite term for office. He was not a candidate to the Supreme Court, a lifetime appointment.
Furthermore, from the time of his defection from the Democratic Party (which was far less liberal in the 60's then in 1988, the time of Harriet Miers defection) to the Republican Party, until the time of his first bid for the presidency, he had built up many and obvious conservative credentials including his enthusiastic and ceaseless attempts to persuade people to it.
There is NO COMPARISON between he and Harriet Miers. It isn't even close.
I'll grant you that he was elected for two terms/8 years, which is very different from a lifetime appointment, with one caveat....if it hadn't finally been formally written into law, after FDR, many here, would have kept on re-electing Reagan,even when he had Alzheimer's; or so they claim today.
That being said, FDR was a Commie coddling socialist, who, Reagan loved and praised all of his life. Yet, he is now so demi deified and mythographized, that facts seem to bother most here; you included. The Dems were far more to the left, in the '30s and '40s than they were in the 1960s. And yes, that is a fact.