There is nothing mysterious about Sen. Tom Coburn’s politics. His political future? That’s another story. Coburn, R-Muskogee, is a staunch conservative, fiscally and politically. Since his election in 2004, he has earned a national reputation as the Senate’s No. 1 opponent of earmarks. He has angered plenty of Democrats, and a few Republicans, by holding up spending bills that he finds distasteful. He would probably have no trouble getting re-elected. A recent survey by SoonerPoll.com showed Coburn’s approval rating among Oklahomans at 60 percent. He showed his potency in 2004 — after entering the race relatively late, he easily dispatched two well-known Republicans before rolling over an incumbent congressman, Brad Carson, in the general election. Yet Coburn has been coy about whether he’ll seek re-election next year. He recently told The Oklahoman he’s on no timetable to decide. His campaign treasury had just $57,000 at last report, and he has done no fundraising to speak of. The reason is classic Coburn: He says it would be wrong to raise money without telling people that he’s definitely going to run. There would be plenty of politicians from both parties lined up to run if Coburn didn’t. But he hasn’t let on as to what he might do. Coburn walked away from his U.S. House seat after three terms. He has indicated he would serve no more than two terms in the Senate. But would he leave after just one? It’s a scenario that could be one of the biggest subplots to the 2010 elections in Oklahoma.