Ideas are not artifacts, especially the kind of collective ideas we know as ideologies. Conservatives in 1964 opposed civil-rights laws. Conservatives in 1974 opposed tax cuts unless paid for by spending cuts. Conservatives in 1984 opposed same-sex marriage. Conservatives in 1994 opposed trade protectionism. Conservatives in 2004 opposed people who equated the FBI and Soviet Union’s KGB. All those statements of conservative ideology have gone by the boards, and one could easily write a similar list of amended views for liberals.
Conservatism is what conservatives think, say, and do. As conservatives change—as much through the harsh fact of death and birth as by the fluctuations of opinion—so does what it means to be a conservative.
On the contray, conservatives believe in a transcendent moral order populated by eternal truths to which they seek to conform human affairs. Jews, for example, recognize these in the Decalogue, Platonists in the Ideas and Hindus in dharma. Infractions committed against the eternal truths do not change the truths, the infractions change us, sometimes for the better but more often for the worse.
Like the sophists, David Frum has chosen the worse, peddling his opinions in a world composed of mere opinion, as changeable as a pair of pants.
That's not conservatism.