Since that meeting, Fed officials, including Bernanke, have signaled that they are unlikely to cut rates more in coming months, given rising energy, food and other commodity costs. The Fed is next scheduled to address rates in late June.
"His resignation shifts the balance a little bit … away from rate cutting, which we already knew," says Brian Wesbury of First Trust Advisors in Illinois. "This will clearly give the regional banks more power."
Gramley says the change won't make an enormous difference, given that the Fed was already moving away from rate cuts.
The Fed is actually even thinner than the numbers suggest, as Fed Gov. Randall Kroszner, one of the five governors currently on the Fed, has a sort of provisional status.
Kroszner's term expired at the end of January. Bush has nominated Kroszner to a full 14-year term, but Senate Banking Committee Chairman Christopher Dodd, D-Conn., hasn't acted on confirmation. Fed policy allows a governor to remain until a successor is named.
In a statement Tuesday, Dodd thanked Mishkin for serving "during one of the most critical and important economic periods of the nation's history" but didn't indicate whether he'd be inclined to revive talks aimed at bulking up the Fed board, at least temporarily.
Aside from Kroszner, stalled Bush Fed nominees are Elizabeth Duke, former chief operating officer of TowneBank of Virginia, and Larry Klane of Capital One Financial, a major credit card issuer.
Before joining the board, Mishkin was a professor at the Columbia University Graduate School of Business. He has also taught at the University of Chicago, Northwestern University and Princeton University.