In his op-ed in the Wall Street Journal, Fred Barnes reports that Donald Trump “plans a series of formal speeches on policy issues, set pieces drafted by speechwriters and delivered from prepared texts… Mr. Trump wants to use the policy speeches to persuade conservatives, among other skeptics, that he is more in sync with their thinking than they imagine.”

Good luck with that.

For reasons Barnes touches on, Trump is widely distrusted by conservatives. A few speeches by him, made at the suggestion of Newt Gingrich — who admits Trump is no conservative! — isn’t going to undo that. For one thing, it is a transparently cynical ploy.

It isn’t simply that Trump isn’t a conservative in the spirit of Goldwater or Reagan; it is that he has been an active opponent of conservatism long ago, recently and to this very day. He has given large sums of money to liberal Democrats. He supported President Obama’s stimulus package. He called for the impeachment of George W. Bush. He is a critic of Paul Ryan and others who want to reform entitlements. He has praised Hillary Clinton as Secretary of State and, during the Republican presidential debates, spoke favorably about a  single payer health care system. He’s a fierce protectionist. The list goes on and on.

But that’s hardly all. Mr. Trump has shown no familiarity with conservatism as a philosophy. As his answers on abortion, health care, the Obamacare mandates, mass deportation of illegal immigrants, how to cut the size of government, the nuclear triad, the Israeli-Palestinian conflict, the Quds Force/Kurds, NATO, seizing Iraqi oil, targeting the families of terrorists and so many other issues show, he hasn’t even thought about most policies. He has no intellectual curiosity, no interest in mastering issues, no ability even to carry on a coherent conversation on most topics. He just wings it, and he does is quite poorly.

But the main objection to Mr. Trump is his temperament. He specializes in stoking resentments and grievances and ugly passions. He condones political violence. Conservatives — those who are paying attention, anyway — know this. A few set speeches he won’t write and will soon forget won’t change any of the basic realities. Donald Trump is a threat to conservatism. Only the foolish will think otherwise.

Peter Wehner is a senior fellow at the Ethics and Public Policy Center and a contributing opinion writer for the New York Times.