W By Ronald Brownstein

ASHINGTON – All of the Democrats actively seeking the party’s presidential nomination pledged their commitment to defend legalized abortion Tuesday night as they opened the struggle for support from a powerful liberal constituency.

In their first joint appearance of the 2004 campaign, the six Democrats who have formally moved toward entering the race competed in declaring their determination to block new restrictions on abortion. They spoke to a crowded fund-raising dinner here for NARAL Pro-Choice America, an abortion rights group formerly known as the National Abortion and Reproductive Rights Action League.

“We will never go back,” said Sen. John F. Kerry, D-Mass. “We will never, ever let this right be taken away.”

Likewise, Rep. Richard A. Gephardt, D-Mo., declared: “There is nothing moral about a presidency that imposes personal morality through acts of governmental power.”

But even as the six Democrats — Sens. John Edwards of North Carolina and Joseph I. Lieberman of Connecticut, former Vermont Gov. Howard Dean and civil rights activist Al Sharpton also spoke — made their statements, abortion rights advocates seemed to raise the bar for measuring commitment to their cause.

In her speech, Kate Michelman, the president of NARAL Pro-Choice America, said she “fully expect(s) pro-choice senators to filibuster” any Supreme Court nominee who does not “affirm that the Constitution protects a woman’s right to choose.”

None of the candidates directly responded to that request.

Overall, the candidates ranked lowest in the national polls — Dean and Sharpton — appeared to generate the most enthusiastic response from the 1,500 activists who gathered to celebrate the 30th anniversary Wednesday of the Supreme Court’s decision in Roe v. Wade that guarantees the legal right to abortion.

Sharpton, who formed a committee to formally explore the race earlier Tuesday, drew enthusiastic cheers when he told the audience that he had stopped to talk with anti-abortion demonstrators outside the hotel where the dinner was held.

“I told them, `It is time for the Christian Right to meet the right Christians,’ ” Sharpton said.

The speeches contrasted sharply with statements by President Bush, an opponent of legalized abortion who declared last Sunday “National Sanctity of Human Life Day.`

In the proclamation accompanying that declaration, Bush stated: “Every child is a priority and a blessing, and I believe that all should be welcomed in life and protected by law.”

Alone among the Democrats who have moved toward entering the 2004 race, Gephardt opposed legal abortion earlier in his career. In the most personal of Tuesday night’s speeches, he offered perhaps his most detailed explanation of his change in thinking.

Gephardt said his initial opposition was rooted in a Baptist upbringing that taught him “abortion was wrong.”

But, he said, years of discussions with colleagues and with women convinced him that “the sanctity of a woman’s right to control her own destiny is a moral force of its own.”

Gephardt remains distinct from his rivals in his votes for legislation to ban the late-term abortion procedure, which critics call “partial-birth abortion,” in all instances except where the life of the mother is endangered.

In 1999, Kerry, Lieberman and Edwards opposed that legislation and voted for a Democratic alternative that would have allowed such abortions to protect a mother’s health, as well as her life. In his speech Tuesday, Dean also said he opposes restrictions on the procedure.

Lieberman struck a more moderate tone than the others. Although he declared his commitment to legalized abortion, he echoed language from former President Clinton in declaring that abortion should be not only “safe” but “rare.`

“Neither side in this debate has a monopoly of values,” Lieberman said in a speech that drew only tepid applause.

Forces on both sides of the debate are converging in a way likely to increase the visibility of the abortion issue in the coming months, and perhaps through the 2004 presidential campaign.

With Republicans now controlling both chambers of Congress and the White House, conservatives are mobilizing to impose new restrictions on abortion.

Anti-abortion leaders say they will renew their push for a ban of late-term abortions. Clinton twice vetoed such legislation, but Bush has indicated that he will sign it.

Liberal groups are gearing up to defend the right to abortion. NARAL Pro-Choice America is launching a effort to organize support for abortion rights that will include television advertising in 15 states critical in the 2004 election, as well as petition drives supporting legislation that would codify the Roe v. Wade decision.

Though there is little likelihood that such legislation will be approved by the Republican-controlled Congress, the group hopes to use the effort as an organizing tool. In his remarks Tuesday night, Edwards promised to “help lead a fight” to pass such legislation.