"As the long and contentious court case drags on before a three-judge panel in Minnesota, it could be weeks, or even months, before either Franken or Coleman is seated."
Their obstructionist ways are aided by the fact that the dems need a minimum of 2 repubs to defect on every piece of legislation instead of 1 if Franken were in the senate. You can see this in the stimulus bill. Dems picked off 3 repubs but it came at a fairly big cost (education rebuilding, health care...)
With the likelyhood that Coleman loses (even he sees the writing on the wall by getting a new job), this lack of a dem senator makes it harder to get to the fillibuster proof majority.