Surprise, surprise: Sen. Ron Wyden (D) has endorsed state Speaker Jeff Merkley (D) in his bid to dethrone Sen. Gordon Smith (R). But what does it mean?

Wyden and Smith have a long-standing nonaggression pact, with both refusing to pointedly attack the other or strongly campaign for each other’s opposition in their past Senate races.

In fact, in a lengthy video of Wyden’s endorsement of Merkley released by the Democratic candidate’s campaign, the Senator did not mention Smith by name. Rather, Wyden attacked Senate Republicans generally while urging a vote for Merkley to increase the Democratic majority and put an end to GOP filibusters.

“A vote for Jeff is a vote to help our new Democratic president begin to repair the damage of the Bush presidency,” Wyden said.

It remains unclear how much public campaigning Wyden will do on Merkley’s behalf in the upcoming general election campaign and how critical he will be of Smith in any campaigning that he does engage in.

The two Senators have lunch once a week when they are in Washington, D.C., and hold joint town hall meetings at the beginning of each Congress. They kicked off the 110th Congress in February of last year with four such meetings throughout the state.

Also, Smith and Wyden collaborate on a list of issues. Their agenda for the current Congress, titled “Senators Smith and Wyden’s 110th Congress Bipartisan Agenda,” was a list of nearly two dozen items that they planned to address by December 2008.

In 1995, Wyden — then a House Member — beat Smith, then the state Senate President, in a heated special election to fill a Senate seat that opened prematurely. Smith won an open Senate seat a year later.

— David M. Drucker