(Updates with Berlusconi says some parties will abstain, para 8) By Stephen Brown ROME, March 26 (Reuters) - Prime Minister Romano Prodi faces a new foreign policy test on Tuesday when the Senate votes on keeping peacekeepers in Afghanistan, where Italy angered allies last week by swapping five Taliban for a kidnapped reporter. Negotiating with the increasingly violent Taliban earned a reprimand from Italy's U.S. and British NATO partners and some domestic foes, who may now withdraw support for the mission. Prodi, who was forced to resign briefly in February after a foreign policy revolt in the Senate, is still expected to win a vote to fund keeping 1,900 troops in Afghanistan. But the debate will highlight his reliance on the votes of opposition or unelected lifetime senators. It will also expose doubts about his centre-left coalition's zeal for the mission. Prodi questioned the patriotism of his rightist predecessor Silvio Berlusconi, saying: "Whoever votes 'no' is trampling on national dignity." The premier said the decree was unchanged in substance since its lower house approval, so foreign policy was being used as "an excuse for discussing the fall of the government". Prodi walks a tightrope in the Senate, where he barely holds a majority. He won a confidence vote there on Feb. 28 thanks largely to the votes of lifetime senators. Critics say he should quit if he cannot get a real political majority. Berlusconi told a rally in Milan on Monday night that most of the opposition would abstain. In the Senate, an absetntion is equivalent to a no vote. DEAL WITH THROAT-CUTTERS Berlusconi sees a chance to undermine Prodi, who ousted him last year. The centre-right leader cites government diplomatic initiatives contradicting his own pro-U.S. and Israel focus. "The country's best interests would be the resignation of this government which has gone arm-in-arm with Hezbollah, given Hamas the nod, made a deal with the throat-cutters and intends to bring terrorists to the negotiating table," said Berlusconi. He was referring to Foreign Minister Massimo D'Alema being pictured with a Hizbollah leader, talking to Hamas Islamists in the Palestinian government -- which D'Alema denies -- and to calls in Italy for Afghan peace talks including the Taliban. But one opposition party, the Union of Christian Democrats (UDC), will vote for the mission but field a motion calling for new rules of engagement to give Italian troops more ability to shoot back, better equipment and even reinforcements. Any move to reinforce troops or give them a more offensive role -- they are not now on the front line -- would cause Prodi big trouble with the pacifist left, who are now toeing the line. Leftists are already paying a political price for this, with one communist leader, Fausto Bertinotti, heckled by students in Rome on Monday with shouts of "Shame!" and "War Mongerer!" UDC support virtually guarantees Prodi the Senate vote but UDC leader Pierferdinando Casini said that if the centre-left could not muster its own majority, he would ask President Giorgio Napolitano "for the Prodi government's resignation".
