The final round of telephone calls to Samuel Rotondi, freshman state senator from Winchester, began Tuesday, the day after his wife gave birth to her third child, a 7-pound, 13-ounce girl.

No one overtly mentioned the baby or the fact it was 10 days overdue. But the calls had all the [WORD ILLEGIBLE] of a sledgehammer.

They were from people who wanted him to vote to override the vetoes of four antiabortion measures, which he has long opposed, when they come before the Massachusetts Senate Monday.

Everyone was very polite, said Rotondi, 30. "But I knew they knew. And I knew that they thought WOULD CHANGE MY VOTE."

It didn't. And the vetoes are expected to be sustained Monday, thus closing the curtain - at least for the few weeks until the new year - on what promises to be one of this state's longest running and most emotionally charged lobbying efforts in recent years.

The controversy around them provides a fascinating glimpse at the politics of the jugular that has overtaken the abortion issue, an issue that tied Congress up in knots for five months and will come before 16 state legislatures next year.

Rotondi, the ninth of 13 children in a strong, Italian-Catholic family, has been in the middle of it since July. He's been denounced from the pulpit ("Sen. Rotondi should re-evaluate his Christianity," he quotes one priest as saying), publicly condemned by the Knights of Columbus and inundated by more than 5,000 letters and phone calls.

"It's hard to fight an issue that comes in the name of the Lord," he says.

Pro-abortion forces used equally fierce, gut-level tactics, bordering at times on political blackmail. "I was subjected to the most vicious, ugly lobbying effort that I've ever seen" declared one of its chief targets. Sen. Chester Atkins, chairman of the state Democratic Party. "It shocked and disappointed me."

But when he and another liberal Democrat, Carol Amick, appeared to waiver on the abortion issue, pro-abortion forces closed in.

"These people were perceived as liberals many of us had helped them in their campaigns. We felt betrayed," said Connie Williams, who headed the lobbying effort for the Massachusetts Citizens for Choice, a "pro-choice" umbrella group.

The group contacted Atkins' financial backers and urged them to tell him they'd never donate to another of his campaigns if he voted with anti-abortion forces. The group sent out leaflets. It orchestrated a parade of constituents to visit his office every day for more than a month.

Rumors that Atkins had gone soft on abortion because his wife was pregnant and that he was trading his abortion vote to get elected state party chairman circulated on Beacon Hill, he says.

Amick, who has just been elected to fill a vacant a seat, came under even more pressure. "At one point a group from NOW [the National Organization for Women] marched into her office and told her they were going to go out and look for another candidate to run against her during the next election," said Williams.

Atkins and Amick eventually joined Rotondi in the core of 15 senators who've voted with pro-abortion forces on all of the recorded votes on the issue.

But what happened to them and other state legislators during the last six months offers a case study in the politics of abortion, a fiercely emotional politics with heavy religious overtones and more losers than winners. But one, nonetheless, that has produced some strange political victors this year - including Gov. Michael Kukakis, who has redeemed his shaky liberal credentials with his stand.

It's easy to exaggerate the state's liberalism. Massachusetts, after all, was the only state to vote for George McGovern for President in 1972. But it is alsot the state the produced Henry Cabot Lodge, who kept the United States out of the League of Nations, and an antibusing battle in 1974 that made the integration of lunch counters in the South look like a church picnic.

It's hard to overstate the role of the Catholic Chuch here this year. Said Senate President Kevin Harrington this week, "There are those who say this represents the last battle to see if the church still as the clout it once had."

The issue began June 30 when Reps. Raymond Flynn, a South Boston Democrat, and Charles R. Doyle, a West Roxbury Democrat, introduced a bill here to cut off state-paid abortions for women covered by medicaid.

Both houses approved it, but it was vetoed by Dukakis, who thus shored up sagging support from liberals. The Senate sustained the veto.

Doyle and Flynn then attached expanded antiabortion language to a state pay-raise bill. The amendments - which would have cut off abortion funds for state workers, including legislators, as well as Medicaid recipients - again passed both houses. But Dukakis vetoed the measure.

For months, the lobbying was intense and well-organized, both on Beacon Hill, where the statehouse is located, and in the legislators' districts.

Massachusetts Citizens for Life, Inc., a five-year old organization with a two-person paid staff, passed out petitions on church steps. "Do not make me an accomplice in the deaths of unborn children . . . Please support the Doyle-Flynn bill," one petition read.

They were from people who wanted him to vote against state funding of abortions for the poor, an issue that has come before the Massachusetts Senate four times this year.

They were from people who wanted him to vote against state funding of abortions for the poor, an issue that has come before the Massachusetts Senate four times this year.

Scores of clergymen wrote to legislators. One priest in the district of Sen. Robert McCarthy told his parish, "Your Irish-Catholic senator is voting with the baby murderers."

Flynn, riding the crest of the antiabortion feeling, was elected to the Boston City Council making him one of the issue's biggest victors.

Meanwhile, 19 groups ranging from the Americans for Democratic Action to the League of Women Voters, were at work on the other side, capitalizing on the anger the issye created among female activitists. They did psychological profiles on 17 senators they thought they could convince to join their camp, and zeroed in on them.