Obama senior advisor David Plouffe ripped the Romney campaign Sunday for criticizing President Obama's foreign policy -- in a German newspaper.

There's a longstanding tradition that politics "stops at the water's edge," when it comes to U.S. foreign policy, but Plouffe said Sunday that Romney stepped over that line with the publication last week of a column that criticized the administration's approach to the Euro crisis.

"It was remarkable," Plouffe said on ABC's This Week. "It was a remarkable thing to see and really unprecedented...

"Europe doing the right things here to stabilize their situation is important to our small businesses, our workers, the middle class here, and overall economy," Plouffe said. "And to inject yourself in this for some short-sighted partisan gain, perhaps, is really unbelievable."

For his part, Romney said on Face the Nation that he wished Obama "would have taken action to rebuild the basis of our economy, its foundation, get it on such a strong footing that the challenges in Europe, if they occur, wouldn't have a significant impact as they might otherwise."

The Romney piece by senior economic adviser Glenn Hubbard, ran in Handelsblatt, a German business newspaper. It took the administration to task for what Hubbard called an "unwise" strategy that showed "ignorance of the causes of the crisis and of a growth trend in the future."

The administration -- which has increasingly cited Europe as a drag on the U.S. economy -- has encouraged European leaders -- German chancellor Angela Merkel in particular, to embrace some growth measures along with the austerity programs it has implemented.

Obama arrives in Mexico tonight for two days of talks at the Group of 20 meeting, which is likely to be dominated by talk of the Eurozone crisis.