The former head of the National Endowment for the Arts under President George H.W. Bush formally entered the race for Gordon Smith's U.S. Senate seat Wednesday, after months of hinting that he might seek the job.

John Frohnmayer will run as an independent in a field that's looking increasingly competitive.

Smith, running for a third term, is considered one of the more vulnerable Republican incumbent senators seeking re-election in 2008. On the Democratic side, House Speaker Jeff Merkley and Portland lawyer and activist Steve Novick are competing for the nomination.

Frohnmayer shares a last name with his better-known brother, Dave, a former GOP gubernatorial candidate who is the president of the University of Oregon. That name recognition could help him in his bid, but independent candidates don't typically make much headway in Oregon.

In a press conference Wednesday at Portland State University, Frohnmayer made clear that he intends to run against political partisanship, a potentially potent argument in a state that's grown accustomed to long legislative sessions and divisive ballot measures.

But he won't be able to draw on any elective experience in his past during his run, and his time at the head of the NEA was rocky. Frohnmayer was fired by then-President Bush in a furor over allegations from conservatives that the endowment subsidized art that was pornographic, sacrilegious or otherwise offensive.

A native of Medford, Frohnmayer worked as a trial lawyer in Oregon and Montana for 25 years. He is a graduate of Stanford University, went to law school at the University of Oregon and spent three years as an officer in Vietnam.