DEMOCRATIC GOV. Hugh Carey of New York said an extraordinary thing the other day. Mr. Carey has endorsed a candidate for his party's nomination to run against Republican Jacob Javits for the Senate in the fall. Several folks are contending for that honor, among them Rep. Elizabeth Holtzman, former mayor John V. Lindsay, Queens District Attorney John Santucci and former city consumer commissioner Bess Myerson. Gov. Carey, along with Sen. Daniel P. Moynihan, endorsed Miss Myerson, and this especially displeased contender Lindsay.So how did Gov. Carey explain? This way:

"You might recall that I said some time back, not as a matter of discriminatory rhetoric, but just as a matter of historical reference, that I consider this as a Jewish [Senate] seat."

A Jewish Senate seat? Pardon us, but we have looked through the U.S. Constitution, the Democratic Party charter, the laws of the Medes and the Persians and the Book of Leviticus and we don't find the authority for this. It is preposterous. And ugly. It was bad enough that people had got to assuming various "seats" -- black, Jewish -- on the Supreme Court. And it is bad enough that some are trying to establish these reservations (as in: this seat is reserved) on certain jobs in the federal government. But to start announcing this as an essential qualification for holding a Senate seat is really grotesque. Gov. Carey, who spent a certain amount of time at the Democratic convention in New York lecturing his fellow Democrats on the wonders and obligations of democracy -- F(3)(c), in case you've forgotten -- should surely know better.

Evidently, where the argument is not strictly a product of a back-to-the-wall need to come up with an "impersonal" explanation, it has something to do with the fact that Herbert Lehman, a Democrat, held the seat before Sen. Javits did. But then, so did John Foster Dulles, and unless he was putting on one of the greatest acts in history, Mr. Dulles was not what you would actually call Jewish. Nor, of course, were others who held the seat in the past.

But merely to point this out is to get into the argument in a way that does no more credit than it deserves. Maybe Mr. Carey is saying that he would vote for a Jewish Republican (e.g., Sen. Javits) over a Prostestant Democrat (e.g., Mr. Lindsay) for this seat. But we doubt it. We think he wasn't saying anything, just talking nonsense.