Former Rep. Tom Campbell (R-Calif.) confirmed Thursday that he is switching from the California governor’s to Senate race, shaking up the GOP primaries for both contests.

In a statement, Campbell said his decision was driven by the growing “need for fiscal restraint in Washington, as well as the fact that he was facing “two billionaires” — former eBay CEO Meg Whitman and state Insurance Commissioner Steve Poizner — in the Republican primary for governor.

“Our country is at a very perilous point in economic terms, and in terms of the size and intrusiveness of government. I believe I can help to restore our nation’s economic health, and spirit of independence,” Campbell concluded.

Campbell’s announcement, which has been rumored for weeks, has already triggered a round of speculation over which existing GOP Senate candidate his move hurts more, former Hewlett-Packard CEO Carly Fiorina or state Assemblyman Chuck DeVore.