BERLIN (Reuters) - German President Christian Wulff faced growing pressure to step aside on Tuesday after several conservative allies turned against him for trying to kill an embarrassing newspaper story on a home loan scandal.
Waning support from parties in Angela Merkel's centre-right coalition, which voted Wulff into office 18 months ago, underscored how precarious his position is and raised the risk of the scandal becoming a major distraction for the chancellor as she grapples with the euro zone debt crisis.
Wulff's resignation would reflect badly on Merkel as she pushed aggressively for his election over a popular opposition candidate in 2010. Finding a successor could also prove a headache, unleashing a divisive political debate when her government needs unity to combat the crisis.
The revelation on Monday that Wulff left an angry voicemail message for the editor of top-selling Bild daily threatening legal action and even "war" if he published a story on a private home loan Wulff agreed at cheap rates has unleashed outrage.
On Tuesday, reporters from another paper, Welt am Sonntag, said Wulff had tried to bully them, too, about a separate story.
The German president is supposed to act as a sort of moral compass for the nation, defending the laws set out in its post-war constitution, which include clear guidelines on press freedom.
Holger Zastrow, deputy chairman of the Free Democrats (FDP) who are junior partners in Merkel's coalition, spoke out against Wulff, who was a top member of Merkel's Christian Democrats (CDU) and state premier of Lower Saxony before becoming president, a largely ceremonial post.
"If a German president personally picks up the phone to ring an editor and leaves a mailbox message, this is not what I expect of a president," he told broadcaster MDR, adding Wulff had "a duty to explain himself."
Other senior conservatives said they expected Wulff, whose next public appearance is scheduled for Friday, to give an account of himself in the coming days.
Wulff did receive support from a CDU official close to Merkel, possibly indicating that her party has not given up on him yet.
"Christian Wulff has apologised for his call to Bild newspaper. This apology was accepted. That should be respected by everyone," CDU General Secretary Hermann Groehe told the Sueddeutsche Zeitung.
Opposition parties took a tougher line.
Thomas Oppermann, a senior Social Democrat (SPD), said time had run out for Wulff. Only a week ago, SPD leader Sigmar Gabriel urged the president to stay in his post, but the party looked to be withdrawing its backing after the Bild revelation.
"The grace period is over," said Oppermann. "No German president is above the law. That applies to press freedom, too. It is absolutely inappropriate if the president is trying to stop free reporting," he said.
The Bild story has left Wulff vulnerable to accusations of hypocrisy. In late December, when he issued an apology for failing to fully spell out the details of the home loan he received when he was a state premier, Wulff also stressed the importance of press freedom.
The loan raised questions about potential conflicts of interest and whether he had misled the state parliament about his ties to a wealthy businessman whose wife granted him the loan.
German media, which had gone quiet on the scandal over the Christmas holiday period, stepped up its criticism of Wulff again.
Stefan Aust, a well-known author and former editor of Der Spiegel weekly, said Wulff appeared to be on a "political suicide mission." "I have never experienced something as insane as this, to be frank," Aust told WDR 2 broadcaster.
Opinion is growing among experts that Wulff, once seen as a potential rival to Merkel, will have to go.
"A German president simply can't put pressure on the press like this. It's not acceptable," Peter Loesche, emeritus professor of political science at Goettingen University said, adding that prospect was unwelcome for Merkel.
"Merkel looks bad for not having vetted Wulff before she nominated him, for failing to check if there were any skeletons in the closet."
Merkel would face the tricky task of finding a new candidate to be elected by the Federal Assembly, where her coalition has a slim 4-seat majority.
But there are no obvious successors. One possibility, Finance Minister Wolfgang Schaeuble, is widely seen as being indispensable in his current job during the euro zone crisis.
Other options could be conservative Labour Minister Ursula von der Leyen, who Merkel passed over in 2010, and the conservative president of the lower house of parliament, Norbert Lammert. Another possibility might be Joachim Gauck, an anti-Communist human rights activist in East Germany who ran against Wulff in 2010 and embarrassed Merkel by forcing the election into a third round.
(Reporting by Madeline Chambers; Additional reporting and editing by Noah Barkin)