The 2013 German elections are irrelevant; Opposition no longer exists in Germany
Heather Hurlburt and Daniel Drezner incorrectly assume that the overwhelming rejection of the Euro-bailout among regular Germans will cause trouble for Merkel and the Eurozone.
For that to happen, there would have to be an opposition that is willing to listen to popular sentiment. But such an opposition does not exist in the Bundestag.
The Social Democrats and the Greens keep haranging Merkel for not having acted faster and bolder and keep demanding that even more souvereignty be confered to the EU and its supra-national institutions.
Merkel had to armwrestle the skeptics among the MEPs of the coalition parties. The Greens and the Social Democrats on the other hand voted almost unanimously in favor.
The Left party voted against the EFSF, but only out of idiosyncratic reasons. They want regulation and nationalization of banks in return, but are not opposed to shoveling of tax payer money out of the country or to ceding sovereignty at all.
Merkel's policies are if anything challenged by the aformentioned skeptics in her own party, who are closest to popular sentiment. But if Merkel is good at anything, it is to solidify her power within the CDU and to purge dissident groups with bullying and other means. (A skill that she probably learned in the former GDR during her training to become a communist apparatschik).