One of the quirks of the unresolved senate race in Minnesota and Illinois is that it really does the Democrats no good to have just one of Al Franken and Roland Burris seated -- they only gain ground if and when both get sworn in.
This is why. Presently the Democrats have a 57-member caucus, counting neither Burris nor Franken. However, because there are currently only 98 senators, this reduces the number of votes required to break a filibuster from 60 to 59. (Vacancies are not counted when calculating the number of votes needed to break a filibuster; three-fifths of 98 is 58.8, which rounds up to 59). Therefore, the Democrats would need two crossover votes to pass a cloture resolution.
But now, suppose that Franken gets seated but Burris doesn't. The Democrats add a member to their caucus, brining them to 58 members. However, with 99 senators rather than 98, the filibuster threshold goes back up to 60 votes (three-fifths of 99 is 59.4, but the rule in this instance requires rounding up). Thus, the Democrats remain two votes shy of breaking a filibuster.
Once the Democrats get senators seated in both Illinois and Minnesota, however, they'll have 59 votes out of the 60 they need, leaving them just one vote shy -- and Sens. Specter, Snowe, et. al. ripe for the picking.
So long as it looked as though the Minnesota race was going to take a long time to resolve, then, the Democrats really weren't giving anything up by failing to seat Burris -- his vote only really helps them if Franken has been seated too. Suddenly, however, with Franken having amassed a 225-vote lead on Norm Coleman, the landscape looks different. While the Coleman campaign is still suggesting that it will contest the election, one wonders what sort of appetite Coleman will have to accumulate more and more legal bills if he determines his situation is hopeless. At the very least, the likelihood has improved that the race will be resolved within two or three weeks, rather than two or three months.
So the stakes are a now a little higher for Harry Reid: Illinois, rather than Minnesota, now appears as though it may be the limiting factor in getting the Democrats into as advantageous a position as possible.
One option that hasn't been much discussed, by the way, is that of seating Burris temporarily and then holding a special election later on. This would allow the Democrats to sort of have their cake and eat it too, getting their 59th vote for several months while still creating a relatively clean break from Blagojevich. Of course, the Democrats would risk losing their seat in the special election, but perhaps the Republicans would reward them for that risk by agreeing to seat Franken while Coleman's election challenges are pending, something they seem disinclined to do so far.