Germany's parliament approved a law today allowing it to contribute to a €750 billion emergency debt package despite broad public opposition to the move.
A clear majority of lawmakers in the lower house backed the bill. But, in a sign of domestic pressure piling on Chancellor Angela Merkel, 10 members of her own centre-right coalition either voted against it or abstained.
The bill will allow Germany to contribute some €148 billion in guarantees to the international package.
Under fire at home for her leadership style in the euro zone debt crisis and from European Union partners over Germany's solo move against speculators this week, Merkel welcomed the vote.
"The governing parties gave a clear message to Europe, for Europe and a clear signal towards a culture of more stability in the euro zone," Ms Merkel told a news conference with British prime minister David Cameron.
The upper house also passed the bill, leaving President Horst Koehler to sign it into law. In the lower house, 319 lawmakers voted for the bill, 195 abstained and 73 voted against - mostly members of the socialist Left party.
The opposition Social Democrats (SPD) and Greens abstained as they wanted a firmer commitment on a financial transaction tax to force the financial sector to bear more of the burden.
In a move at least partly designed to assuage hostile public opinion about bailouts for weaker euro zone states, Germany shook markets this week by banning some speculative trades or naked short sales - irking EU peers, who were not consulted.
SPD leader Sigmar Gabriel accused Ms Merkel of losing all credibility. "You have no direction, you have no goal," he told the Chancellor, adding her tactics had lost the confidence of Europe.
To add to her woes, a survey for ZDF television showed 51 per cent of Germans polled opposed the euro zone aid package and 54 per cent said Ms Merkel was giving too little leadership.
Faced with such stiff public opposition, Ms Merkel and her Finance Minister Wolfgang Schaeuble argue the unpopular package is essential to protect the euro which has fallen roughly 5.5 per cent against the dollar this month.
"We're doing this in our best national interests ... the common European currency has been a huge benefit to Germany," Mr Schaeuble said in an impassioned speech before the vote, arguing almost two thirds of exports go to members of the euro zone.
"Without the euro, we would have a much weaker economy, a much weaker Germany," he said, adding Germany is still pushing for tougher rules on euro zone deficits.
Germans resent forking out for weaker euro zone members. They fear a bulging deficit of their own and do not want to help states that have been less rigorous in budget discipline.
Voters in the state of North Rhine-Westphalia punished Ms Merkel's centre-right coalition in a regional vote earlier this month that was overshadowed by a row over the debt crisis.
The overall aid package includes €440 billion in guarantees from EU states plus €60 billion in a European instrument and €250 billion from the IMF. It is on top of a €22.4 billion euro contribution from Germany to an international rescue plan for debt-ridden Greece, approved just two weeks ago.