One of the big questions about Donald Trump is whether he can find a running mate. It’s going to be difficult — what with all the insults he’s hurled at his fellow Republicans — to find a member of the Party of Lincoln who is prepared to stand with him. Particularly because the pith down to which his economic program can be boiled is protectionism. The GOP is the free-trade, free-enterprise party, the free minds and free markets party. Hence the difficulty finding Mr. Trump a Republican running mate.

So here’s a possible ticket — Trump-Schumer. If The Donald gets the nod at the top of the ballot, the most logical running made for him would be Senator Charles Schumer. One may be a Republican and the other a Democrat, indeed the most partisan of Democrats and the senator most likely to lead the Democratic caucus in the next Senate. But partisanship has become a dirty word in modern politics, and on the central feature of Trumpism, The Donald and Mr. Schumer are two peas in a pod.

Certainly Mr. Schumer is no stranger to protectionism. And he’s not too particular about his allies. In 2004, he co-authorized a piece for the New York Times with the economist Paul Craig Roberts. A brilliant intellect, Professor Roberts was associate editor of the editorial page of the Wall Street Journal. He went to work for President Reagan as Assistant Secretary of the Treasury and then broke away from the supply-side movement and fetched up in league with Mr. Schumer and the Times.

Their joint op-ed piece was called “Second Thoughts on Free Trade.” It ran in the New York Times in January 2004. They expressed concern that America was “entering a new economic era” in which “any worker whose job does not require daily face-to-face interaction is now in jeopardy of being replaced by a lower-paid, equally skilled worker thousands of miles away.” They blamed “multinational corporations, often with American roots, that are cutting costs by shifting operations to low-wage countries.”

“Most economists want to view these changes through the classic prism of ‘free trade,’ and they label any challenge as protectionism,” Messrs. Schumer and Roberts wrote. “But these new developments call into question some of the key assumptions supporting the doctrine of free trade.” And so began the strange romance between a rightist faction among economists and the Democratic dalliance with xenophobia. Could this also be the beginnings of a political romance between the two New Yorkers?

Particularly because Messrs. Trump and Schumer — Trumer, as they’re known in certain circles — are constantly carrying on about currency manipulation. Mr. Trump talks about it all the time, blaming the Communist Chinese and the Japanese for taking advantage of us through manipulating their currencies. Yet Mr. Schumer has been hauling wood for this bonfire for years. As recently as last year, he got the Senate to pass a measure against currency manipulation that was opposed by his own president.

“It’s long past due for the United States government to take on the world’s worst currency manipulators and level the playing field for American workers and companies,” Mr. Schumer said at the time, which was in May of last year. A few months later, Mr. Trump was quoted by Politico as insisting that America must “stand up to China’s blackmail” and adding: “The U.S. Treasury’s designation of China as a currency manipulator will force China to the negotiating table.”

In other words, Messrs. Trump and Schumer are made for each other, and it would be useful for the Republicans to mark the point. The Republicans have more principled, less xenophobic answers to the problems on which Messrs. Trump and Schumer are resorting to demagoguery. They would drop punitive American tax rates and welcome home trillions in capital being parked overseas by American corporations, who will then be able to put the capital to work here at home.

They would pass (and a president like Ted Cruz would sign) audit the Fed, which would restore to the branch to which the Constitution granted the monetary powers the authority to look into the international dealings of the Federal Reserve. They would move to repeal Humphrey-Hawkins, getting the Fed out of the business of watching the unemployment rate. The Republicans would take a new look at the gold standard that undergirded our eras of greatest growth. If Mr. Cruz is the candidate and stands on these principles, he’ll have no trouble finding a running mate — from within his own party.