By Christiaan Hetzner
STUTTGART, Germany (Reuters) - Chancellor Angela Merkel's conservatives appeared set to lose power in a major regional stronghold on Sunday after early results suggested the anti-nuclear Greens were surging to their first ever state premiership.
In Baden-Wuerttemberg state, where anti-nuclear sentiment has been mobilized by Japan's nuclear crisis, the Greens and Social Democrats (SPD) were set to win 48.3 percent, eclipsing the Christian Democrats who have held power for six decades.
Merkel's CDU and their Free Democrat coalition partners, big backers of nuclear power, won a combined 43.2 percent, according to the first projections after polls closed at 1600 GMT in the state of nearly 11 million people.
"It's very painful," said Merkel's Education Minister Annette Schavan, a CDU leader in Baden-Wuerttemberg.
The CDU, which has governed the state for 58 years, took 38.2 percent and the FDP 5. The Greens finished second with 24.9 percent and the SPD, their likely allies, took 23.4 percent.
The Greens' 13 percent advance was mirrored in another state election on Sunday in Rhineland-Palatinate, where the SPD held onto power and was likely to form a coalition with the Greens.
FOREIGN EVENTS BLAMED
Economy Minister Rainer Bruedele from the FDP called his party's ejection from Rhineland-Palatinate's assembly a "bitter defeat" and blamed "events in Japan, war in Libya and the euro debate."
Last month Merkel's conservatives were ousted in Hamburg in a state election and lost control of North Rhine-Westphalia, Germany's most populous state, last May.
She has already lost her majority in the upper house of parliament, or Bundesrat, where the 16 states are represented, and further gains for the opposition mean her ability to pass some legislation will be severely limited.
Merkel's policy U-turns on nuclear power, military action in Libya and the euro zone debt crisis turned the closely-watched Baden-Wuerttenberg contest into a virtual a referendum on the performance of her 1 1/2-year-old center-right government.
She abruptly shut down seven of Germany's 17 nuclear plants right after the disaster in Japan and put on ice plans to extend the use of atomic energy by 12 years from 2022 -- moves that voters and analysts described as a campaign ploy.
"This is the beginning of the end for Merkel," said Lienhard Bauer, a 53-year-old banker in Stuttgart. "I've been a CDU party member for more than 30 years but I didn't vote CDU this time."
Merkel's future could now be cast into question. After her SPD predecessor as chancellor, Gerhard Schroeder, lost North Rhine-Westphalia in 2005, he called a snap election and lost.
Anti-nuclear sentiment and criticism of Merkel's confused stance were big issues in a state where environmentalists were already mobilized by opposition to a major infrastructure program in the state capital, a railway project in Stuttgart.
(Writing by Erik Kirschbaum and Stephen Brown; additing reporting by Brian Rohan; editing by Ralph Boulton)