Earlier today (3/25) Steve King (R IA04) told reporters that his odds of running for the open senate seat being vacated by Tom Harkin are "a little more than 50-50."
Congressman Bruce Braley (D IA01) has already announced his candidacy. Braley probably has the Democratic nomination locked up. If King runs, polls indicate that he would easily win the GOP nomination. King is popular with the Republican base, especially the Tea Party. A Braley-King race would be a clear contrast between a popular center-left congressman and a leading member of the far-right wing of the House Republicans.
Whether King will or will not run is a source of speculation in the state. One person who follows King closely is political reporter Brett Hayworth of the Sioux City Journal. Hayworth rates the odds of King running for senate as 67%. A contrary view has been expressed by desmoinesdem in her blog, Bleeding Heartland. She says flat out, "Steve King is not running." and she make a good case why he would choose not to run.
My take on this: desmoinesdem makes a persuasive case for a rational person. But this is Steve King. His policy positions are based on ideology, frequently in direct contradiction to the evidence. He has to be tempted by the opportunity to move to a bigger stage where he could continue to promote his ideological clap trap and save the country from Obamacare, foreign-speaking immigrants, gun grabbers, and other threats to his neighbors in his Kiron home town. A Public Policy poll shows that Braley would beat King by 11 points. That's evidence. But King is not known for paying attention to evidence.
The one person with the best insight to his decision-making process is King himself. If he says the odds are "a little more than 50-50," I'll take him at his word. One thing about King is that if he makes a statement or takes a position, he sticks with it forever, no matter how stupid or wrong it proves to be.