An earlier version of this column included an incorrect reference to Larry Kudlow’s religious affiliation and incorrectly stated that Goldman Sachs’s Lloyd Blankfein had announced his retirement. The column has been corrected.

As it turns out, Donald Trump—who constantly whines about “fake news”— admits he totally made up stuff about the U.S. trade deficit when discussing it with Justin Trudeau, the leader of our largest trade partner, Canada. Trump admitted last night that he was clueless about whether we have a deficit with Canada, but just assumed we do “because we’re so stupid.”

For the record, the Office of the United States Trade Representative says the United States—which the president oversees—acknowledges that America has a trade surplus with Canada.

Into this swamp of presidential ignorance and dishonesty steps Larry Kudlow, the new economic adviser. Why, he’s just the right man for the job. After all, he’s for free trade, tax cuts and a strong dollar DXY, -0.09% , a big change from former adviser Gary Cohn, who was for free trade, tax cuts and a strong dollar. Wait, what?

It’s true. There’s no daylight between Cohn and Kudlow on the big stuff. And Cohn was even more qualified, frankly. Once the No. 2 guy at investment-banking powerhouse Goldman Sachs GS, -0.44% —had he stuck around, he might have been in a position to replace longtime CEO Lloyd Blankfein, reported to be headed toward retirement (but denying the reports)—he was also shortlisted to replace Janet Yellen as Federal Reserve chair. A lot of Trump’s hires have been outright mediocrities, but Cohn, refreshingly, wasn’t one of them.

It all went downhill last year, though, when the Jewish Cohn let it be known that he was offended at the president’s equivocation on the matter of Nazis marching in Charlottesville, Va. Trump didn’t like that. The final straw came with Trump’s recent tariffs on steel and aluminum, which could be the opening salvos in a damaging trade war.

Given that Kudlow is a free trader, there are already bets on how long he’ll last under this president. Perhaps the elixir of such a big White House job and the ego validation of flying on Air Force One is such that he’s willing to look the other way on Nazis and trade wars, but we’ll find out soon enough.

What attracted the president and “Kuddles” (as his friends call him) in the first place? The principal reason, and perhaps the only reason, is that Kudlow, like Trump, spent years on TV—a stamp of approval in Trump’s simple mind—talking about the economy. There’s no question that Kudlow is passionate and articulate, and knows his stuff and how Washington works—among his many jobs was working in Ronald Reagan’s Office of Management and Budget nearly 40 years ago.

But Kudlow left Reagan’s employ because he was unhappy that Reagan was jacking up the deficit with tax cuts. That didn’t seem fiscally prudent, so Kudlow, who was then in his mid-30s, just walked away. Yet President Trump is doing the very same thing: He just signed a tax-cut bill that will push long-term deficits sharply higher. For the record, it’s worth noting that Kudlow’s concerns about Reagan’s spendthrift ways were not misplaced: The national debt tripled during the 1980s.

There are, however, things about Kudlow that raise eyebrows. Just this week he told his employer CNBC that “the United States could lead a coalition of large trading partners and allies against China,” and that would show Beijing that Washington means business. You know what that coalition would be called? The Trans-Pacific Partnership, or TPP—and Trump pulled out it of shortly after taking office. China isn’t a member of TPP, and Trump’s withdrawal is seen in Beijing as a great gift—and a sign of American decline.

And Kudlow has made some enormous and stupendously bad calls. In the fall of 2007, when the housing and stock markets were collapsing, he downplayed it, writing in National Review that, “Despite all the doom and gloom from the economic pessimistas, the resilient U.S economy continues moving ahead quarter after quarter, year after year, defying dire forecasts and delivering positive growth.” Looking ahead to 2008—when the entire U.S. economy came crashing down and millions of Americans lost their jobs, and banks, automobile makers and mortgage lenders had it be bailed out to the tune of hundreds of billions of taxpayer dollars—he said “we are about to enter the seventh consecutive year of the Bush boom.”

Anyone who thinks otherwise, he added with flair, “are going to wind up with egg on their faces.”

But wait: There’s more. Here’s one from 1993: “There is no question that President Clinton’s across-the-board tax increases on labor, capital and energy will throw a wet blanket over the recovery and depress the economy’s long-run potential,” Kudlow wrote. What happened next? The U.S. economy began an eight-year expansion, creating 21 million jobs—and the federal budget was balanced.

Let’s hope that Kudlow’s forecasting skills have improved with age.