By Stephen Brown
BERLIN (Reuters) - Chancellor Angela Merkel's challenger in the approaching German election, Peer Steinbrueck, took a stark stance against Western military action in Syria on Friday in a play to anti-war sentiment ahead of their only TV duel in the campaign.
After two days of telephone diplomacy by Merkel, who faces a tricky balancing act between backing Germany's allies while heeding German voters' opposition to an attack, Steinbrueck tried to differentiate himself in typically blunt style.
"I want to make it quite clear for myself and for the SPD (Social Democrats) that we believe a military intervention would be wrong because we cannot see how it would help the people in Syria," the center-left politician told reporters.
Steinbrueck, 66, is struggling to make a dent in the conservative chancellor's popularity ahead of the September 22 election, when she will be seeking a third term.
He may hope to boost his chances by heeding pacifist strains in German society, especially on the left, as SPD chancellor Gerhard Schroeder did in his 2002 campaign by staunchly opposing the U.S.-led invasion of Iraq.
The SPD wants to help the international community "break out of this military logic", said Steinbrueck, proposing that the U.S. and Russian presidents and the heads of the United Nations and Arab League focus instead on negotiating a ceasefire.
Merkel has said that Syrian President Bashar-al Assad's government, embroiled in civil war with rebels, should not go unpunished over what the United States said was its use of internationally banned chemical weapons on August 21, an attack that killed hundreds of civilians in a Damascus suburb.
But she has not explicitly come out publicly in favor of military action, for which Washington is preparing. Assad has denied resorting to poison gas, blaming rebels for the attack.
Asked on Friday about Merkel's telephone conversations on Syria with Obama and other leaders, her spokesman Steffen Seibert told a news conference there had been no request for German involvement in any military strike against Damascus.
Steinbrueck and Merkel will be mindful, in their live TV debate on Sunday, of the public mood in Germany when it comes to a possible military strike against Damascus.
Polls show overwhelming distaste for any military action - and especially for any German participation - meaning Berlin may have to stand aside, as it did on Libya two years ago.
Many Germans are instinctively averse to foreign military involvement given the nation's Nazi past, when it started World War Two and perpetrated the Holocaust.
(Editing by Gareth Jones and Mark Heinrich)