The CDU now seems poised to lose a major stronghold to a Green Party-led coalition in a key state.
Green Party members were celebrating a major triumph Sunday in the prosperous southwestern state of Baden-Wurtternberg, ruled by the CDU since 1953 and home to 11 million people.
Early results showed that Merkel's party won 39% of the popular vote in Baden-Wurtternberg but failed to gain a majority. The Greens, which won 24.2% of the votes, are expected to form a coalition with the Social Democrats, which polled 23%.
This will be the first time a liberal Green Party premier will be elected in Baden-Wurtternberg, known for its conservative, pro-business voting practices.2011 nike running shoes online
Japan's nuclear disaster had a big role in this shift, analysts say, as German voters expressed their historic aversion to nuclear energy in the wake of Japan's nuclear disaster.
On Saturday, tens of thousands of Germans took to the streets to protest against nuclear power. Germany was affected by the radioactivity from the 1986 Chernobyl disaster.
CNN's Berlin Bureau Chief Fred Pleitgen said Merkel's swift change in nuclear policy has had a big effect on this year's election.
Germany's 17 nuclear plants are under a three-month safety review imposed after the Fukushima nuclear disaster. The oldest seven of the plants will remain shut during the review.buy Reebok EasyTone
Germany's Spiegel Magazine has made the claim that the government's recent and sudden decision to temporarily shut down the seven reactors was politically motivated, an attempt to allay fears of a home-grown nuclear disaster, allegations the government denies.
"Merkel's snap decision left plenty of people across Germany scratching their heads. It was only last autumn that her government spent significant quantities of political capital in its move to extend nuclear reactor lifespans in the country," the magazine reported.