Germany may be America's most important European ally, but the relationship between the two countries is on the rocks.

On Thursday, Germany expelled a top CIA agent from Berlin, a highly unusual move for which the German government cited a "lack of cooperation" from the United States in clarifying recent spying cases.

Those cases include revelation that the CIA tried to recruit a German secret service staffer to sell classified information, and the possibility that a German Defense Ministry employee had been working for U.S. intelligence. German policymakers and journalists are up in arms, with U.S. diplomats struggling to contain the political damage.

In a recent poll, only 35% of Germans said the United States can be trusted. This is a stunning vote of no confidence amid continued public uproar about the NSA's tapping of Chancellor Angela Merkel's cell phone.

For those dedicated to the trans-Atlantic alliance, the current atmosphere is more depressing than during the height of the Iraq war, when Chancellor Gerhard Schroeder and President George W. Bush made no secret of their antipathy. Long gone are times like when 200,000 Germans cheered for candidate Barack Obama as he spoke under Berlin's Victory Column in summer 2008. Gone, too, are Obama's 75% approval ratings among Germans.

Read more on CNN