In the anti-abortion movement's tiny, cramped political command center in the National Press Building, the message is being sent out that the tide turned and politicians better beware.

"We've proven our point," declares Paul Brown, director of the movement's political action committee. "There is a pro-life vote. We've come of age as a political force."

A few feet away, a young assistant is on the telephone asking a housewife in Wisconsin to defeat congressmen and senators in areas "where a strong pro-life vote of 5 to 8 percent can make a difference." "We've proven this works," the woman is told, "in places like Iowa where we elected Roger Jepsen and in those two Senate races in Minnesota" where Republicans took both seats.

Brown's nessletters take the same tack. They boast of replacing "abortionists Dick Clark, Tom McIntyre and Floyd Haskell" with "strong pro-life leaders Roger Jepsen, Gordon Humphrey and Bill Armstrong" in Senate races in Iowa, New Hampshire and Colorado.

Those claims, according to those most familiar with the campaigns, are an oversimplication at best, a gross exaggeration at worst.

" what they sid was to look at elections where people who happened to oppose their positions lost and then they said 'we won them,'" says Karen Mulhauser, head of the National Abortion Rights Action League (NARAL), a leading "pro-choice" group.

But her coments illustrate the diffculty groups like NARAL and candidates who support their views face in dealing with the volatile politics of abortion.

It's a problem that is certain to intensify in minths ahead, posing special headaches for liberals in the House and Senate attempting to judge the real or imagined ballot power of pro-life forces.

Brown's group, the Life Amendment Political Action Commitee (LAPAC), has already raised hackles on Capitol Hill by issuing a 1980 'hit list" -- dubbed the "deadly dozen.'

The list is headed by such well-known liberals as Sen. Birch Bayh (D-Ind.), Sen. George McGovern (D-S.D.), Sen. Frank Church (D-Ariz.). NARAL's Mulhauser charges this indicates "they're out to get liberals and they're joining forces with the rest of the right wing. They simply don't target conservatives.'

The list does have a decidedly left-of-center cast. Only three Rpublicans, all moderates -- Sen. Robert Packwood of Oregon, Rep. John Anderson of Illinois and Rep. Harold C. Hollenbeck of New Jersey -- appear on it.

The others named are: Sen. Patrick J. Leahy (D-Vt.), Sen. John Culver (D-Iowa). Rep. Robert Edgar (D-Pa.), Rep. Joseph Fisher (D-Va.) and Rep. Robert Drinan (D-MASS.)

But there's no clear pattern to those on the list. Bayh, McGovern, Packwood and Drinan, a Catholic priest, are longtime targets of anti-abortion forces. Hollenbeck, however, voted with the antiabortion forces 40 percent of the time last year, according to a NARAL index; Church voted with them two-thirds of the time.

While Fisher is on the list, Rep. Herb Harris, a Democrat from a neighboring Northern Virginia district, is not, although their viting records on abortions questions are identical.

"I'm puzzled by it, but I'm not losing any sleep about it," says Fisher, the father of seven. "I guess I'm saddened more than anything. I don't like to be on anyone's hit list."

Church was outrged when he found himself among "the deadly dozen."

'The accusation that I advocated abortion on demand is an outlandish baldfaced lie," he told a press conference in Boise last month. "On the abortion issue my position has always been decidedly conservative... I intend to pin to the wall any allegations that misrepresent my position."

In drawing up the list, LAPAC considered the voting records and vulnerability of candidates as well as the strength of pro-life groups in their areas. "We can't go out and defeat everyone we don't like,' says LAPAC director Brown. "So we picked a few where we think we can make a difference.'

The group's ultimate litmus test for any officeholder is whether or not he supports a constitutional amendment prohibiting abortion.

With a budget last year of only $100,000, LAPAC has few real resources of its own. It was formed as an independent political action commitee, supposedly free from any formal ties to other anti-abortion groups -- a legal distinction that permits it to raise money from the general public rather than the membership of any one group.

But LAPAC opponets question how independent it really is. LAPAC's chairman is Sean Morton Downey Jr., a longtime lobbyist for the National Right to lefe Committee. Brown's wife is the director of that group. "You might say we're in bed with the National Right to Life Committee," Brown says.

Last fall, LAPAC made cash contributions to several candidates, set up a telephone bank in New Hampshire manned by Brbara Baroody, a Brown assistant, and paid for the printing of 30,000 leftlets in Iowa attacking Sen. Dick Clark's stand on abortion. Clark opposed a constitutional amendment and had voted to permit abortions under some