My friend Jonah Goldberg has written a column entitled Conservative Purists Are Capitulating With Support of Trump. Jonah goes after me and Stephen Moore for allegedly giving up our free-market principles for what he calls purely consequentialist reasons. I am not sure of the full meaning of this phrase, but it sounds like weve changed our beliefs because Mr. Trump is the leading candidate in the GOP presidential race.

Jonah is an old and valued friend, and I respect and admire him enormously. I wish I could write as well as he does  even when he comes after me. But I want to set the record straight on a number of points where I think Jonah gets it wrong.

First, Steve Moore and I continue to oppose Donald Trumps trade policies. Even if his 45% tariff threat on China is simply a negotiating card, as Mr. Trump told me in recent interviews, we still think thats the wrong way to go.

Speaking for myself, I believe China is a major trade violator. The Chinese break all the rules. They counterfeit our goods, steal our international property rights, and cyber-hack our industries and government. Something must be done about it. But a 45% tariff would be a major tax on American consumers and businesses. It would probably do more damage to our economy than to Chinas.

Now, I think we need a strong president to enforce current trading laws between the America, China, and the World Trade Organization. Perhaps some targeted economic sanctions on Chinese companies could work. For example, the U.S. has decided to sanction Chinese telecom giant ZTE for trade violations with Iran. This is a more precise response to trade violations than a 45% tax.

Mr. Trump may well have the presidential leadership skills to solve the China problem without resorting to economy-wrecking tariffs. But at the moment Steve Moore and I disagree with him on this topic.

Second, Jonah argues that I have moved markedly in Trumps direction on immigration. Here are the facts: In mid-December, I wrote a piece in which I announced a much tougher position on immigration  a big change in my thinking. But this had nothing to do with Mr. Trump. It was all about the war against ISIS.

The full title: Ive Changed. This Is War. Seal the Borders. Stop the Visas. I argued for a wartime moratorium on new visas and new immigrants because of the substantial danger of ISIS terrorists infiltrating our system. The piece was written just after the horrific attacks in Paris and San Bernardino. I argued that until FBI director James Comey gives a green light to new visas, and not until we completely reform the vetting process for new foreign visitors, that the borders should be sealed.

War brought me to this position. My only mention of Mr. Trump was when I disagreed with him for singling out Muslims. My proposal was not based on religion, but on the threat of ISIS infiltration into the United States. There was nothing consequentialist about it.

Finally, I have for many months endorsed Trumps tax-cut plan. In particular, I like his business-tax-cut strategy, which includes a 15% rate for large C-corps and small S-corps along with easier repatriation and cash-expensing write-offs for new business investment. I think its an excellent plan that would substantially grow the American economy and bring trillions of dollars in overseas capital back to the U.S., which in turn would foster millions of new jobs and faster growth.

Whats more, a number of think tanks believe the biggest beneficiaries of a significant corporate tax cut would be middle- and lower-middle-income wage earners. They, by the way, have not had a raise since 2000, which is probably why theyre opposed to trade deals and illegal immigrants, too.

In the Michigan Republican primary exit poll, 33% said trade expansion would create more American jobs while 54% said it would take away U.S. jobs. I prefer an economic-growth solution to this middle-class angst, not a protectionist program. I think Mr. Trumps business-tax-cut package would lessen trade fears by providing wage earners with a significant pay boost.

So, yes. I have endorsed Trumps tax-cut plan.

On the other hand, I have not endorsed any GOP candidate. So, in answer to my friend Jonah Goldberg, I believe I am sticking to my pro-growth, supply-side strategies of lower tax rates and free trade. Regarding immigration, where I have changed my view, thats all about the war against ISIS. I want to assure my friend Jonah that I have not experienced any Pauline conversions on the road to a Trump presidency.