By Erik Kirschbaum
BERLIN (Reuters) - Chancellor Angela Merkel's humbling defeat in accepting an opposition candidate for president may herald a shift in coalition alliances that could yet see her conservatives unceremoniously bundled from power in 2013.
Merkel herself is riding high in opinion polls, the public generally satisfied with steady if unspectacular leadership during the euro zone debt crisis. Her center-right coalition will likely remain together until the 2013 election.
But her junior coalition allies, the Free Democrats(FDP), unexpectedly turned on her at the weekend and backed opposition candidate Joachim Gauck to replace disgraced former president Christian Wulff. Though the President has little political power, the act itself was seen as a personal political betrayal of the chancellor and the coalition by many Merkel loyalists.
What appeared unthinkable a week ago, now seems at least a theoretical possibility; in German politics, a sea change.
More worrying for Merkel's Christian Democrats (CDU) than the humiliation of seeing the man Merkel vowed would "never" become president forced upon them is the way the FDP pushed open a door for a possible three-way coalition with the opposition Social Democrats (SPD) and Greens after the 2013 poll.
It is a nightmare encirclement scenario for the CDU and their Bavarian sister party, the Christian Social Union (CSU). In the 2013 ballot they could win more votes than any other party. But they could still end up in opposition if the three smaller parties SPD, Greens and FDP unite to form a coalition.
"Merkel got blindsided by the FDP and without even realizing what's happened, the whole political situation has changed," said a senior CDU source. "The FDP had a strategy. She didn't. No one warned her this might happen. It was a terrible blunder."
The ex-minister added: "Everyone underestimated the FDP. With one stroke the FDP is a player. There's suddenly a new coalition possibility for 2013 that doesn't include us."
Few thought it would be even remotely possible before Sunday's remarkable turn of events that the FDP would be a possible ally of the SPD and Greens - even though such three-way "traffic light" coalitions have been tried in two states.
But with the FDP risking a rupture of the center-right coalition to back Gauck, the specter of a future federal government without the CDU is now on strategists' minds even though it is still seen as unlikely and Merkel has climbed to new heights in popularity.
"This was a very strong signal sent by the FDP and it opens up a new spectrum of coalition options," said Hans Vorlaender, political scientist at Dresden's Technische Universitaet.
"It's a major surprise. It has loosened up the two blocs. The center-right and center-left aren't as set in stone as they were before. The FDP outmaneuvered Merkel and re-established their independence with this. That will certainly help the FDP."
The SPD, Greens and FDP would not quite have enough seats to form a coalition in parliament right now but could in 2013. A more likely scenario if the center-right coalition were to falter would be a grand coalition of the CDU/CSU and SPD.
"I'd expect the FDP to quiet down a bit and be happy to keep this coalition together until 2013," the CDU official said. He added the prospect the FDP could switch allegiances should help it rise to the 5 percent threshold needed for parliament seats.
The FDP is largely a pro-business, centrist party, economically liberal, socially conservative and traditionally pro-Europe, though it has at times resisted Euro zone rescue plans for Greece. In the post-World War Two era, its kingmaker role was long seen as a force for continuity in German politics.
However, a three-way SPD-Greens-FDP coalition would likely be less stable than a grand coalition after 2013, analysts said. The two SPD-Greens-FDP coalitions at the state level both collapsed in mid-term: in Brandenburg and Bremen.
There would be built-in turbulence as the FDP and Greens are arch enemies. Also, a three-way coalition would struggle to get legislation through the Bundesrat, the upper house of parliament, where it is unlikely to have a majority.
"These 'traffic light' coalitions have always collapsed before the end of the term in the states so I don't think it's going to happen any time soon at the federal level," Manfred Guellner, head of the Forsa polling institute, told Reuters. "There are too many differences that can't be glossed over."
But FDP officials are clearly savoring the moment and glad that the CDU/CSU is taking them seriously again.
Merkel's conservatives are well ahead of the center-left SPD in polls, holding a 38 percent to 29 percent lead. But she needs a coalition partner and the FDP is down to about 3 percent from the 14.6 percent it won in 2009 -- thus short of a majority.
As a result of the FDP's weakness, the conservatives have run roughshod over the small centrist party for the last two years even though the FDP was for decades the kingmaker in West German and later German politics as it shifted strategically back and forth between the CDU/CSU and SPD.
"The CDU has been treating the FDP poorly," the CDU source said, noting ex chancellor Helmut Kohl was a master in making sure the FDP got a share of the spoils. "A coalition is only as successful if all parties have something to show for it."
The FDP has fallen on hard times, in part because it had sworn a Nibelungen-like fealty to the CDU/CSU and repeatedly ruled out a coalition with the center-left. That changed on Sunday and analysts expect the FDP to rise back toward the 5 percent level after so boldly reasserting itself.
The SPD is polling 29 percent and Greens at about 15 percent are also short of a majority. Before Sunday, the thinking in Berlin was that a Merkel third term would be with either the SPD in a grand coalition or possibly a coalition with the Greens.
Those odds have now fallen, analysts and sources said, with the emergence of another option: SPD-Greens-FDP. The SPD in the past has formed coalitions with the FDP even though the CDU/CSU won more votes. That last happened in 1980. The SPD also came in second to the CDU/CSU in 2005 but still formed a SPD-Greens coalition that kept the conservatives in opposition.
The CDU/CSU has beaten the SPD in 15 of 17 post-war elections but the SPD still managed to lead six governments.
ANGRY MERKEL ERUPTS
Merkel and her conservatives tried desperately to prevent Gauck even though opinion polls showed the man only narrowly defeated in 2010 by Wulff was by far the public's most popular choice. He was nominated again by the SPD and Greens.
Merkel tried to divide the two opposition parties. She first attempted to lure the SPD away from Gauck with other candidates with appeal to the SPD but that failed -- the FDP watched in horror, fearing those candidates would be a precursor of a grand coalition of CDU/CSU and SPD after the 2013 election.
She then tried to entice the Greens away from Gauck by proposing Klaus Toepfer, a former CDU environment minister former and head of the U.N. Environment Program (UNEP). The FDP feared that would signal a CDU/CSU-Greens coalition in 2013.
That is when the FDP bolted and came out publicly for Gauck. Merkel warned FDP leader Philipp Roesler there would be "serious consequences" which was widely understood to mean an end of the coalition.
"Is that what you really want?" Merkel reportedly told Roesler. The normally unflappable Merkel began shouting during the tense hours Sunday evening in the chancellery, according to conservative daily Frankfurter Allgemeine Zeitung.
Roesler told Die Welt Merkel's reaction to the FDP support for Gauck was "very strong." He added: "The conservatives repeatedly pointed out that the coalition could be ended."
Merkel has since tried to put a positive spin on Gauck. But her conservative allies have attacked the FDP in unusually harsh language, calling the move a massive breach of trust.
IN BED WITH ENEMY
"I find it incredible that the FDP have got into bed with the SPD and Greens on this," said Michael Meister, deputy parliamentary floor leader for the CDU. "That cannot be allowed to happen again," he told the Cologne Stadt-Anzeiger daily.
Merkel is also aware that elections for the largely ceremonial office as president have served as a prelude for changes in the federal government or shifts in political sentiment nationally.
In March 1969, the then-opposition FDP helped elect SPD candidate Gustav Heinemann president. Six months later after the next parliamentary election the SPD and FDP formed a SPD-FDP coalition that ruled until 1982 when the FDP switched its allegiance back to the CDU/CSU.
In 1993, the CDU candidate Roman Herzog unexpectedly when the SPD made a strategic blunder. The SPD then lost the parliamentary elections in 1994 even though they had been well ahead of the CDU/CSU in polls before the presidential vote.
"Merkel wanted to send a signal for a CDU-SPD coalition or a CDU-Greens coalition with her various choices but the FDP knocked the ball out of her hands," said Vorlaender. "Now they've sent their own signal (for a SPD-Greens-FDP coalition). There's still a long way to go until 2013. But suddenly there is another option that few had on their radar before."
(Reporting By Erik Kirschbaum)