Germany's main opposition party, the Social Democrats of Merkel challenger Peer Steinbrueck, finished a distant second in Bavaria with 20.6 percent. That was two percentage points better than the post-World War II low they hit five years ago, but too little to give them any hope of unseating the conservatives or much national momentum.
And their allies, the Greens, slipped to a disappointing 8.6 percent.
"This is a great election success," Bavarian governor Horst Seehofer, the CSU leader, told supporters in Munich. The CSU has led Bavaria since 1957, most of that time with an absolute majority.
"With this, the year 2008 is history," Seehofer said. "We're back."
In Berlin, a somber Vice Chancellor Philipp Roesler, the Free Democrats' leader, sought to rally his party which governed Bavaria with Seehofer for the past five years. It's also weak in national polls, hovering around the 5 percent needed to keep its seats in the national Parliament.
"We all know that things are different in Bavaria and from now on, it's all about Germany," Roesler said. "And this result is a wake-up call."
Challenger Steinbrueck's Social Democrats pointed to the positive, citing their modest gains in a state where they usually struggle and vowing to step up their own national campaign.
Steinbrueck said Sunday's election added to a string of votes in which voters have failed to endorse a conservative-Free Democrat coalition "and prospects are good for that being the case at federal level in a week's time."
Merkel, who has campaigned hard against her center-left opponents' plans for tax increases, has benefited in the national campaign from Germany's strong economy and low unemployment.
That's even more of an advantage in Bavaria, the tradition-minded homeland of retired Pope Benedict XVI and also a high-tech and industrial center, where nearly 9.5 million people were eligible to vote. Its jobless rate is just 3.8 percent, the lowest of any German state and well below the national average of 6.8 percent.
Still, the Free Democrats' weakness may be a problem for Merkel. Sunday's outcome opens up the possibility of Merkel supporters switching their votes to the smaller party to ensure it tops 5 percent in the national election, which would weaken her conservatives.
"Those who want Angela Merkel must vote for Angela Merkel," Armin Laschet, a deputy leader of the chancellor's party, told ARD television. The Free Democrats "will make it," he added.
The smaller party has been a fixture in post-World War II Germany's national Parliament but isn't traditionally strong in Bavaria.
National polls show Merkel's conservative bloc of her CDU and the Bavaria-only CSU leading the pack.
However, they show her current center-right coalition roughly level with the combined opposition, and holding an advantage of about 10 points over Steinbrueck's over hoped-for alliance of his Social Democrats and the Greens.
That suggests Merkel may need to form a new coalition, perhaps a "grand coalition" with the Social Democrats the combination with which she ran Germany from 2005-9.
In Bavaria, a center-right party that's strong locally but not nationally, the Free Voters, took 9 percent of the vote. A new anti-euro party that is running in the national election, Alternative for Germany, didn't field candidates on Sunday.
