SEN. JACOB JAVITS, who until Tuesday was undefeated in campaigns of all kinds since 1946, but who had failed to win a majority of the votes cast in any of those general elections since 1962, lost the Republican Senate primary to Alfonse D'Amato, the presiding supervisor of the Long Island town of Hempstead, Mr. D'Amato, who had previously been named the Senate nominee of the third and fourth most popular parties in the state -- the Conservative Party and the Right-to-Life Party -- will now have three lines on the November ballot.Sen. Javits insists he will run on the Liberal line against Rep. Elizabeth Holtzman, who won the Democratic nomination for the Senate on Tuesday. All of this has more than a little to do with presidential politics and a lot to say about New York politics.

One of the more persistent myths in American politics is that New York, especially New York City, is some sort of exotic liberal-leftish place. Simply not true. Richard Nixon won 59 percent of the state's vote in 1972 and 48 percent of the New York City vote that year. Both Los Angeles and Chicago, to say nothing of Boston and Cleveland, were far more enthusiastic about Democrat George McGovern than were New Yorkers. New York also elected Conservative James Buckeley to the Senate in 1970 and that same, year returned Gov. Nelson Rockefeller, running as an all-out nemesis of narcotics and drugs, to his fourth term in Albany.

But it was that man, the late Nelson Rockefeller, who did as much as anyone to keep alive the belief that the liberal New York Republicans, at least, were still alive and well. Gov. Rockefeller simply vetoed any primary bill that came across his desk. Through the force of his leadership, his energy and his personal resources (none of which he was ever reluctant to employ in a campaign), Gov. Rockefeller totally dominated the New York Republican Party and prevented debilitating and destructive primaries. Because of his unorthodox record, with its appeal to Liberals and Democrats, Jacob Javits was always a formidable general election candidate and a vulnerable primary election candidate who needed that protective umbrella Gov. Rockefeller provided.

Sen. Javits has now vowed to fight on with his name on the Liberal Party line, at the same time reaffirming his personal support for Republican presidential nominee Ronald Reagan. In doing the latter, Mr. Javits is failing to support his ticket-mate on the Liberal Party line: Rep. John Anderson of Illinois. But with the added activity that a Javits campaign would almost inevitably produce, it seems that Mr. Anderson would almost surely benefit or, at the very least, that President Jimmy Carter and the Democrats would not be much helped.

Rhetorical excess did not take a holiday in New York, you will be relieved to learn. Rep. Holtzman observed Tuesday night that her victory in the Democratic primary merely proved that someone who "stood up to the machine" could still win.

With the characteristic light touch that has made him better respected than loved in the Senate, Sen. Javits attributed his defeat to "the fact that I didn't bring my fantastic record before the people."

In the case of the New York "machine" to which Miss Holtzman referred in her own victory statement, it might help to remember that this was New York's second primary of the year. In the April presidential primary, New York City Mayor Edward Koch, the most popular officeholder in the city, according to impartial surveys endorsed President Carter. Gov. Hugh Carey and Sen. Daniel Patrick Moynihan did not endorse a presidential candidate. Sen. Edward Kennedy won the New York presidential primary handily.

This time, Mayor Koch was joined by Gov. Carey and Sen. Moynihan in endorsing former New York City consumer commissioner Bess Myerson in the Senate primary. It must be inspection time for the "machine." Won't someone call the Maytag repairman?