HOUSTON — The Republican Convention on Monday adopted a stringent, anti-abortion platform plank that disgruntled abortion rights advocates predicted would hurt President Bush's prospects for reelection in November.

"It's a terrible mistake," said Rep. Bill Green (R-N.Y.), referring to the platform plank. "It can hurt the ticket. It can hurt party candidates all down the line."

To register their objections, abortion rights advocates wore pink satin armbands that were clearly visible in all parts of the convention hall as the party platform was passed by voice vote. But a small chorus of "no" votes was quickly drowned out by the cheers of victorious conservatives, who had succeeded in retaining the party's 1988 anti-abortion plank.

Conservatives minimized the political impact of the decision. "We have won three landslides on that platform," said Rep. Robert S. Walker (R-Pa.). "We'll soon see the issue of abortion become secondary in importance to the economy and world leadership."

Still, the vote did not lay the matter to rest.

Abortion rights delegates vowed to return to the 1996 Republican convention with the strength to reverse the party's stand on the issue. And, in the meantime, it was clear that abortion would continue to divide the party.

Responding to charges that the platform might deprive him of victory, Bush said in an interview on Monday that he is still "unashamedly pro-life."

But unlike Bush's personal view, which allows for abortion in cases of rape, incest or a threat to the life of the mother, the Republican Party platform would permit no exceptions. It proclaims that "the unborn child has a fundamental individual right to life which cannot be infringed" under any circumstances and calls for the appointment of judges who hold that view.

Republicans in favor of abortion rights insist that an overwhelming majority of GOP rank-and-file members side with them on the issue. According to some polls, as many as 71% of the Republican Party favors a woman's right to chose whether she will have an abortion.

The platform vote was a disappointing defeat for those activists who had tried to mount a petition campaign to get sufficient signatures to bring the matter up for a roll-call vote. They were overwhelmed by a highly organized defensive effort by Bush-Quayle operatives who wanted to avoid an embarrassing floor fight.