New York’s Republican primary is set for Tuesday, and, in the most important race, it looks like the last-minute momentum is with David Malpass for Senate. The New York Sun was the first newspaper to endorse Mr. Malpass. We did so in an editorial back in June, and he’s been looking better with every week. It’s hard to remember a candidate in a state-wide race in New York who has exhibited a better, clearer grasp of the issues. In the particular economic crisis our country is facing today, he towers over the Democrat place-holder, Kirsten Gillibrand. It would not be too much to say that, on the basis of the campaign so far, one can predict that Mr. Malpass would emerge as an intellectual leader within the Senate from the moment he got there.

This is underscored by the growing list of endorsements of Mr. Malpass, including high-octane statements from Mayor Giuliani, the New York Post, Steve Forbes, and John Faso — and a host of regional leaders, such as state senator John DeFrancisco and Assemblyman Michael Fitzpatrick. The point that is becoming ever clearer is that leading our country out of the current crisis is going to require an understanding of economics and business, an appreciation for markets, and a principled stand against excessive taxation. On these issues there is no one who can touch Mr. Malpass, who has been in this struggle since the Reagan administration, in which he held a senior post in Treasury.

It is in the nature of Republican politics in New York that there is a good bit of skepticism at the outset. Mr. Malpass has been battling against the old patronage system in Nassau and Westchester counties, where the machines are supporting their native sons. But the new wave of the party is with him; in a three way race at the Republican Convention in June, 33 of New York’s 62 counties at the Republican Convention endorsed Mr. Malpass. The energy of the Tea Party movement has been swinging behind Mr. Malpass, with FreedomWorks endorsing him as one of their eight nation-wide senate candidates. Mr. Malpass was petitioned onto the November ballot on the Taxpayer line, a process by which the Working Families and the Conservative Parties came into being in earlier years.

At the outset many reckoned that Mr. Malpass, who is not a career politician, had a slim chance of success. But it turns out that the lanky economist — who has an ebullient wife and a joyful family of four children — turns out to be a natural at the political game. No doubt this is one reason why over the weekend one the most respected political prognosticators, John Fund of the Wall Street Journal, declared that a political upset might be in the works in the Senate race. Of Mr. Malpass’s two primary opponents, Mr. Fund noted, one, Bruce Blakeman, is “burdened by his ties to a discredited GOP machine in Nassau County” and the other, Joe DioGuardi, has been, at age 70, out of office for over two decades.

People say that a Republican can’t win in New York, but New York City elects Republican mayors, the five largest counties in the state all have Republican chief executives, and the last successful governor was a three-term Republican. Mr. Fund pointed out Sunday that any GOP nominee will be “at a clear disadvantage in financing and campaign infrastructure against Senator Gillibrand.” But, he noted, Ms. Gillibrand is “on the wrong side of key issues for many voters.” She is a high tax, high-spending candidate — in her few months as an appointed senator she has “spent,” meaning voted to spend, an astonishing $5 trillion of other people’s money — making her just the kind of politician to put into sharp relief the virtues of Mr. Malpass. A long-time New Yorker, he has roots in a part of Michigan that is much like upstate New York. He has a profound understanding of Wall Street. He is the taxpayer’s friend. So if the GOP nominates Mr. Malpass, the upset that the Wall Street Journal wrote of could well become a reality.