By Christiaan Hetzner
MUNICH (Reuters) - Angela Merkel's allies swept to victory in a state election in Bavaria on Sunday, regaining the absolute assembly majority they lost in 2008 and providing a show of conservative strength for the chancellor a week before Germany goes to the polls.
The Christian Social Union (CSU), sister party of Merkel's Christian Democrats (CDU), won 49 percent according to TV projections, putting them back more firmly in the saddle of a prosperous southern state they have governed for 56 years.
But the Bavarian ballot also delivered a worrying message for Merkel, as the pro-business Free Democrats (FDP), with whom she governs Germany in a center-right coalition, slumped to just 3 percent, falling below the 5 percent theshold needed to get assembly seats.
It was a thumping victory for Bavaria state premier Horst Seehofer, who had told Merkel his party's success would set the mood for the national poll on September 22.
"The CSU is a people's party and we are deeply rooted in the Bavarian population. Every second Bavarian voted for us," he told a crowd of cheering supporters.
The FDP tried to find brave words after Sunday's disastrous result, which thwarted recent upward momentum for the party.
"This is a heavy defeat for the FDP in Bavaria. But our response now is: let's get going ... Bavaria is different. Now it is about Germany," said party leader Philipp Roesler, calling it a "wake-up call" for all liberals.
Merkel, whose conservative bloc stands at around 40 percent, needs the FDP to do well in the federal vote to avoid having to turn to the opposition Social Democrats (SPD), with whom she governed in her first term from 2005-2009. The FDP stands at around 5-6 percent nationally.
Its poor showing in Bavaria might scare conservatives into giving their second vote to the FDP, potentially weakening the share of votes for Merkel's CDU. Germans pick a constituency candidate with their first vote, and the second vote determines the relative strength of the parties in the Bundestag.
Projections put the SPD on 21 percent in Bavaria and their Greens partners on 8.5 percent. The Freie Waehler (Free Voters), a Bavarian party which opposes Germany's euro zone policy, polled 8.5 percent.
Bavaria is home to 12.5 million of Germany's 80.5 million people and if it were a country, it would have the euro zone's sixth largest population and economy. The state cherishes its strong regional identity and is fiercely proud of its careful state spending and "laptop and lederhosen" economy.
It is the only state with a regional party in the federal parliament because when other regional conservative parties joined to form the CDU, the CSU chose to remain separate. CSU lawmakers make up nearly a quarter of Merkel's bloc.
The party was dealt a blow in 2008's regional election when it slumped to 43 percent, forcing it into a coalition with the FDP.
(Writing by Alexandra Hudson, Michelle Martin and Erik Kirschbaum; Editing by Stephen Brown and Alison Williams)