WASHINGTON, D.C.: With one compromise measure voted down and another likely to fail as well, Republican Senators worked through public debate, private arm-twisting and a furious grassroots campaign to line up the necessary votes to pass their bill outlawing partial-birth abortions even as the Clinton Administration was twisting a few arms of its own. The debate centered on whether to adopt the Democratic proposal, sponsored by Minority Leader Tom Daschle, to allow some exceptions for third-trimester abortions or the Republican push to outlaw all abortions performed by the partial-birth method. In highly charged speeches, California Senator Barbara Boxer charged that passing the GOP bill was the first step on the slippery slope towards banning all abortions: "What this is really about is outlawing one procedure and then they'll go after the next procedure and then they'll go after the next and the next." Nonsense, said Pensylvania's Rick Santorum, the bill's sponsor. "Open your heart to these babies," he said in a Senate floor speech, flanked by images of aborted fetuses. "Don't let this kind of barbarism continue. Stop the murder. Stop the infanticide." A final vote is not expected until as late as next Tuesday.