Sen. John McCain and other Republicans want an independent special prosecutor to investigate. Feinstein prefers Attorney General Eric Holder's decision to assign two U.S. attorneys to probe the leaks. For one thing, it's quicker.
But also, it's not clear that a special prosecutor could do much about leaks from political aides. Former Dick Cheney aide Scooter Libby was convicted not for leaking the identity of former CIA operative Valerie Plame but for lying about it. If aides say they didn't know something was classified or if they can show they were authorized to speak, it seems there is no crime.
At Friday's news conference, Obama said: "The notion that my White House would purposely release classified national security information is offensive. It's wrong." But what if aides leaked key intelligence accidentally on purpose?
Feinstein is working on new administrative procedures to curb leaks. Violators, she explained, might lose their security clearance -- or their jobs.
The real problem seems to be rot at the top. How do you impose the need for silence about underwear bombs or phony vaccines when White House stars are bragging about their exploits in The New York Times?
Remember the Libby trial. Washington clamored for Libby's scalp for a leak that did less damage than the likely fallout from leaks on thumb drives, double agents and vital assets. Considering what's at stake, there should have been 99 senators and one president standing with Dianne Feinstein.