In my previous piece in this series, I quoted a Ronald Reagan speech to CPAC, the Conservative Political Action Conference, from February 6, 1977, where Reagan defined conservatism. Among his crucial points in that speech — a point he would reiterate for years to come — is that conservatism was an ideology of principle, grounded in principles, and thus conservatives, too, must be grounded in principle.

Looking to win the White House for conservatism after the wilderness years of Nixon and Ford and now amid what would be a disastrous Jimmy Carter presidency, Reagan said it was time at last for a principled politics for conservatives. They needed “to present a program of action,” one that included both social conservatism and economic conservatism. They needed to defend both the family and limited government, both faith and freedom, both the dignity of the human person and lower taxes. Each side, the social and economic, was half of a “politically effective” conservative whole that needed communicated, needed shared, needed boldly expressed, needed to be not afraid, so that Americans everywhere understood that conservatism provided a good and natural political home.

I could spend much time here delineating the numerous ways in which Reagan held to that position as president, though I really don’t need to, given that no one ever doubted Ronald Reagan’s principles as president. Both sides, from left to right, knew where Reagan stood on issues from limited government to fighting the Soviets.

Reagan’s sense of conviction was legendary. From Tip O'Neill to Ted Kennedy, the widely perceived sense of Reagan’s sureness, of his grounding in certain fundamentals, was respected even by those who disagreed with his policies. The public understood where he stood. In 1986, independent pollster Gerald Goldhaber found that nearly 70 percent of the American people could name at least one of Reagan’s top four priorities. By contrast, such ratings for the LBJ, Nixon, Ford, and Carter administrations ranged from 15 to 45 percent.

When Reagan steadfastly refused any concessions on SDI from Gorbachev at Reykjavik in October 1986 and other summits, it was a natural extension of his bedrock commitment to principle.

Here, I’ll focus briefly on merely one such Reagan commitment: tax cuts. It was one era where I had initially thought that Donald Trump (to his credit) might share some similarity with Reagan.

The reduction of the federal income tax was the centerpiece of Reagan’s economic agenda. Reagan secured a 25 percent across-the-board reduction in tax rates over a three-year period (5 percent-10 percent-10 percent) beginning in October 1981. Eventually, through these and later cuts, the upper income marginal tax rate was dropped from 70 percent to 28 percent by the end of Reagan’s presidency.

In the process, Reagan also dramatically simplified the tax code. When he was inaugurated, there were 16 separate tax brackets, each applied to varying levels of income. When Reagan was finished, there were only two brackets. Not only did this simplification eliminate complexity, it also eliminated loopholes and removed some four million working poor from the tax rolls; they no longer paid any federal income tax.

Liberals today like to argue that Reagan “increased taxes.” They obfuscate the issue. Reagan indeed occasionally compromised with Democrats (who controlled Congress) on tax increases in order to pass a budget. For instance, Reagan agreed to increase excise taxes (on gasoline) in 1982, the Social Security payroll tax in 1983, and smaller tax rises in 1984 and 1987. His willingness to compromise came in exchange for promised spending cuts, which Reagan hoped would thereby reduce the deficit. In 1982, Congressional Democrats promised Reagan spending cuts in exchange for a tax increase by a ratio of three to one. It seemed like a superb deal, but the promised cuts never came.

Significantly, however, these tax increases did not involve income taxes. As Reagan biographer Steve Hayward notes, Reagan “never budged an inch on marginal income tax rates.” Reagan understood that not all taxes, or tax increases, are equal.

Ultimately, Reagan presided over the largest tax cut in American history, and accomplished it working in tandem with (rather than against) a huge Democratic Party majority in the House. And after a slow start through 1982-83, the stimulus effect of the Reagan tax cuts was extraordinary, sparking the longest peacetime expansion/recovery in the nation’s history: 92 consecutive months, far surpassing the previous record of 58 months. The bogeymen of the 1970s — chronic unemployment and the deadly combination of double-digit inflation and interest rates — were vanquished. The poverty rate dropped. Incomes (median earnings) and standard of living jumped up. The Dow Jones Industrial Average, which, in real terms, had declined by 70 percent from 1967-82, nearly tripled from 1983-89.

But here is my point today: The pressure upon Reagan to reverse course on cutting income taxes when they initially seemed to be working only very slowly at best was immense. Still, Reagan did not give in. Why? Because he was principled. Because he was devoted to a principled conservative philosophy.

As one Reagan adviser told Time magazine during the lingering recession of 1982-83, when the stimulative effect of Reagan’s tax cuts seemed slow in sparking the economy, “He is absolutely convinced that there will be a big recovery…. He is an optimist. My God is he an optimist!”

He stayed the course.

This brings me to Donald Trump on cutting federal income taxes. Again, this is a policy area where I had believed that Reagan and Trump share some commonality. And yet, Trump a few weeks ago was already reneging. In a matter of minutes a few Sundays ago, from ABC to NBC, Trump took flight on taxes, soaring all over the studio, and seemingly reversing himself, at least momentarily.

This was and remains immensely frustrating, especially to Reagan conservatives. We watched Reagan spend eight years sticking to his principles on income taxes. Here, now, it isn’t even the convention yet, and the presumptive Republican presidential nominee seems to already be shifting on taxes.

Frankly, I am hoping that as former Reaganite advisers counsel Trump on tax cuts, as they (including Art Laffer and Larry Kudlow) are reportedly doing, that they might be able to hold him to some consistency and accountability if he became president. But alas, if they do, such would be a testimony to their commitment to principle, not Trump’s. That is because, again, Trump lacks principles in a way that Reagan never did. On this, let’s let him speak for himself:

About three weeks ago on Fox & Friends, Trump said that everything he says is a “suggestion.” He was pressed regarding his comments about temporarily banning Muslims from entering the country, which he qualified as having been “just a suggestion.” “Yeah, it was a suggestion,” said Trump. “Look, anything I say right now, I’m not the president.” He stated emphatically: “Everything is a suggestion, no matter what you say, it’s a suggestion.”

His official campaign, Paul Manafort, quite amazingly, backed his man’s inability to stand firm: “He’s already started moderating on that,” said Manafort. “He operates by starting the conversation at the outer edges and then brings it back towards the middle. Within his comfort zone, he’ll soften it some more. He’ll still end up outside of the norm, but in line with what the American people are thinking.”

Really? Well, sure. This is easy for Trump to do because he is not a conservative of principle, nor someone running for office of any clear discernible governing philosophy whatsoever. Donald Trump is precisely the kind of unmoored power-seeker that founders like Jefferson, Adams, Madison, and Hamilton warned about.

More statements from Trump:

In February, Trump told Fox’s Greta Van Susteren that once the original 17-candidate GOP presidential field dwindled, he would be changing very rapidly. “We started off … 17 people. Now we’re down to not very many people,” he said. “And once you get to a certain level, it changes. I will be changing very rapidly.”

He will be changing very rapidly? When? How?

Here, on this occasion, Trump seemed to be talking about his behavior, his temperament, how he acts on the campaign trail, where, frankly, there has been no clear change at all, even as all of the remaining 17 have exited the race and as he now stands alone as the presumptive nominee.

“I’m very capable of changing to anything I want to change to,” Trump told Greta in what should be viewed as a defining statement.

For these reasons, sources from left to right, from Salon to Mark Levin to Glenn Beck, have described Trump as a Chameleon. Detailing his flip-flopping on tax cuts and minimum wage, The Atlantic labeled him, “Donald Trump, Chameleon Extraordinaire.”

This is now painfully obvious to everyone, and should be even to Trump’s devoted followers. Some saw it right away.

A forerunner was Rand Paul, himself a man of strong principle. Speaking a year ago (last summer), Paul warned of Trump: “I have no idea if he’s conservative…. He is such a chameleon that he has been on every side of every issue. Wake up, America!”

(For the record, and as a not-so-minor parenthetical, I think that Rand Paul could be a last-minute third-party alternative that conservatives have been looking for — one who could appeal to elements of the right and left and middle from domestic to foreign policy. If he needs any advice on this, he might talk to his dad.)

This lack of principles from Trump should alarm those supporting him who claim to be principled conservatives. This political chameleon is one who ought to give them pause. He is a political animal who certainly bears no comparison to Ronald Reagan.