When the 105th Congress convened in January, about 115 members represented the state of Washington. That number will drop by one, in the March 6 special election for the Senate seat vacated by Republican Sen. Jim DeMint, when Democrat Don Benton steps down. Benton, the secretary of state, is the favorite, but at least one big name is running: former New York City Mayor Michael Bloomberg.

Bloomberg’s decision to challenge Benton should be applauded. One could argue that neither Bloomberg, who has spent more than $2 billion on civic activism in his lifetime, nor Benton, a former GOP congressman, will cut much of a fist-sized dent into the Republican Party, but at least they’re being honest about their bid. In the past, Bloomberg has openly derided and rejected presidential candidates and his affiliation with Republicans is well-known. Benton’s habit of relying on opinion polls as a basis for selecting his political ideology probably didn’t earn him many friends either. But their presidential dreams are all for naught: With his new online Senate seat, Benton won’t be able to run against his own party for another four years.

Bloomberg, however, will be boxed in. He might have an easier time challenging Democrats in a state where Democrats outnumber Republicans 2-to-1. But Washington is a highly polarized state, with single-digit partisan margins in a region home to many national media outlets. Wearing his large super PAC name around his neck, and talking about marijuana legalization, climate change, women’s reproductive rights and gun control might help his chances. But that brand likely would be an even more unpleasant challenge in a Republican-heavy state than a swing one. At the very least, Bloomberg will find it hard to distinguish himself from the two other candidates in the Democratic primary, each of whom are seen as far more mainstream by Washington’s political elite. The four lesser-known candidates running are all right-wing Republicans or centrist Democrats. The chances of a Bloomberg-voting primary electorate are slim to none.