Sen. Dianne Feinstein (D-Calif.) has been generally supportive of the National Security Agency, over which she plays a top oversight role as the chair of the Senate Intelligence Committee, praising its chief and calling Edward Snowden's leaks "an act of treason." But the past week of revelations about U.S. eavesdropping practices – particularly allegations that the NSA may have tapped German Chancellor Angela Merkel's cellphone – seem to have pushed her too far.

Feinstein's office released an unequivocally critical statement Monday evening, saying she is "totally opposed" to spying on the leaders of allied countries and calling for a "total review" of U.S. intelligence programs. She calls the reported monitoring of Merkel's cellphone "a big problem." That might not sound like particularly severe language, but it's a significant turn for Feinstein, who's been an important ally for the Obama administration in the past months of controversy of U.S. spying programs. Her congressional oversight committee, she says, "was not satisfactorily informed."

In her statement, Feinstein articulates a line for what it and is not acceptable when it comes to "this type of surveillance": it's okay if the U.S. is "engaged in hostilities" with that country or there's an emergency, she says. Otherwise, not okay. In other words, she doesn't think that spying on the leaders of allies is a good idea. (Read this piece by Marc Ambinder to get a sense of why U.S. intelligence officials might believe spying on allies is both acceptable and a good idea.)

Here's the statement, worth reading in full:

It is abundantly clear that a total review of all intelligence programs is necessary so that members of the Senate Intelligence Committee are fully informed as to what is actually being carried out by the intelligence community.
Unlike NSA’s collection of phone records under a court order, it is clear to me that certain surveillance activities have been in effect for more than a decade and that the Senate Intelligence Committee was not satisfactorily informed. Therefore our oversight needs to be strengthened and increased.
With respect to NSA collection of intelligence on leaders of U.S. allies — including France, Spain, Mexico and Germany – let me state unequivocally: I am totally opposed.
Unless the United States is engaged in hostilities against a country or there is an emergency need for this type of surveillance, I do not believe the United States should be collecting phone calls or emails of friendly presidents and prime ministers. The president should be required to approve any collection of this sort.
It is my understanding that President Obama was not aware Chancellor Merkel’s communications were being collected since 2002. That is a big problem.
The White House has informed me that collection on our allies will not continue, which I support. But as far as I’m concerned, Congress needs to know exactly what our intelligence community is doing. To that end, the committee will initiate a major review into all intelligence collection programs.