The Senate yesterday again approved legislation to ban what critics call "partial-birth" abortions but fell narrowly short of the two-thirds majority that would be required to override a promised veto by President Clinton.

In what officials said was probably the Senate's first vote ever on 1973 Supreme Court decision legalizing abortions, the Senate also voted 51 to 47 to go on record endorsing the Roe v. Wade decision as "an important constitutional right" that should not be overturned.

Forty-five of the Senate's 54 Republicans voted against the proposal sponsored by Sen. Tom Harkin (D-Iowa); it was supported by all but two Democrats. Democrats used this nonbinding vote to contend that Republicans were using the "partial-birth" abortion issue as a smoke screen to mask an assault on abortion rights of all kinds and predicted it would be a big issue in next year's elections.

Republicans denied the charge and described Harkin's proposal as a "distraction" aimed at diverting attention from "partial-birth" abortions. But it was clear that, just as Republicans have used the vote on the bill against Democrats and will do so again, Democrats now intend to use the Roe v. Wade vote against Republicans.

The vote on the "partial-birth" abortion bill was 63 to 34, with 49 Republicans and 14 Democrats supporting it and 31 Democrats and three Republicans opposing it. Counting absentees, the bill's backers registered a net gain of one vote since it came up for a vote last year but were still at least one and probably two votes short of the 67 needed to ensure a veto override. Among those who did not vote yesterday was Sen. John H. Chafee (R-R.I.), who has previously voted against the measure.

Sen. John W. Warner (R-Va.) was the only Washington area senator to vote for the bill, although he supported the resolution backing Roe v. Wade.

The bill, sponsored by Sen. Rick Santorum (R-Pa.), would ban a procedure, known medically as intact dilation and extraction, under which a physician pulls the fetus out of the birth canal feet first then then punctures the head, removes the brain and collapses the skull. The fetus is then removed vaginally.

It would make it a felony punishable by a fine and up to two years in prison for a physician to employ the procedure unless it is "necessary to save the life of a mother whose life is endangered by physical disorder, illness or injury." The woman would not be subject to prosecution.

The bill's supporters argued it was necessary to prevent "infanticide . . . wanton destruction of the most vulnerable in our society," as Santorum put it. Foes charged it was unconstitutional, dangerous to women, so loosely drawn it could threaten many abortions by other procedures and politically inspired.

The White House issued a statement Wednesday saying the bill "contains the same serious flaws" as legislation that Clinton vetoed in 1996 and 1997 and so the president will also veto the latest version.

The House and Senate have approved similar legislation several times since Republicans took control of Congress in 1995, and Clinton has vetoed it twice. The House has produced more than enough votes to override Clinton's vetoes in the past but has not yet acted this year. Late-term abortion bans have been approved by 29 states, but courts have blocked or limited enforcement in 19 states, according to the American Civil Liberties Union.

As the Senate opened debate on the measure Wednesday, it rejected, 61 to 38, an alternative that would have banned all abortions after fetuses can survive outside the womb.