The long-awaited Senate debate on abortion developed into a contest of political wits and parliamentary maneuvering last night.

Under pressure from colleagues, Sen. Bob Packwood (R-Ore.), leader of a filibuster against anti-abortion legislation, and Sen. Jesse Helms (R-N.C.), author of the legislation, jockeyed for tactical advantage.

Packwood won the only victory of the day, and a minor one at that, with a parliamentary move designed to limit Helms' ability to amend the legislation more than once.

This move was blocked, but Packwood is expected to try again today as his filibuster enters its third day. He will hold the upper hand because he was appointed temporary Republican floor manager of a debt-ceiling bill to which Helms has attached his anti-abortion amendment.

The move was significant because Helms has introduced his anti-abortion amendment only partially, keeping its precise language to himself in a bid for advantage. As of last night, the amendment contained only two words -- "Title II" -- leaving colleagues in the dark.

Helms, an outspoken conservative, told the Senate that he was negotiating the language with Sen. Mark O. Hatfield (R-Ore.), who could help marshal the support of moderates.

"This is the only shot we'll have," Helms said, "and so we'd better take our best shot at it. I am counting heads. I am counting votes. I am not engaging in any subterfuge."

Packwood, however, attacked Helms for dilatory tactics. "I'm in a position of shooting at a moving target, and I don't know what the target is," he said.

Both he and Helms were under pressure yesterday from Senate Republicans, eager to finish business for a Labor Day recess expected to begin this week, to agree to a time limit on the abortion issue. Packwood said he could not, because of the uncertainty over the language.

Helms has circulated two drafts of his amendment. One has a provision that would prohibit federal courts from ruling on state laws relating to voluntary prayer in public schools. The other deals only with abortion.

Helms, who earlier reneged on a time agreement for the abortion debate, said he's now willing "to end debate after 30 minutes."

"Nobody has anything new to say on this issue," he said.

Both of his drafts would modify the toughest provision of a "unity bill" that anti-abortion groups have rallied around for months. That provision would define human life as beginning at conception and would place fetuses under the protection of the Constitution. Helms told the Senate he had dropped that provision because it did not have the votes to pass.

Packwood said he had mounted his filibuster because he didn't think he could defeat Helms' watered-down proposals.

Both drafts include a host of other provisions designed to limit abortions. They would restrict the use of federal funds for abortion permanently, something Congress has done for the past six years in riders to appropriations bills.

They would also prohibit federal employes' health insurance from paying for abortions, and the use of federal funds for abortion-related research.

The drafts also declare that the Supreme Court "erred" in its 1973 Roe vs. Wade decision, which legalized abortion, and would provide for an expeditious Supreme Court review of cases arising from state abortion laws.

Baker, who urged Helms and Packwood to come to a time agreement, said he had no immediate plans to move to cut off the filibuster, and was considering keeping the Senate in session through the weekend.

Proponents of legalized abortion yesterday accused Helms of retreating because his original proposal had no chance of passage.

"In a cynical attempt to snatch some vestige of victory from certain defeat, Sen. Helms has constructed a crazy quilt of anti-abortion legislation," said Marguerite Beck-Rex, spokesman for the National Abortion Rights Action League.

Although split over Helms' latest approach, most anti-abortion groups indicated support for the measure.

"Anything that puts these guys on record this close before an election is good for us," said Peter Gemma, executive director of the National Pro-Life Political Action Committee. "We'll take anything we can get at this point."