So you think that if he switches parties, he would switch actions?
Reid has not been single-handedly forcing his will upon either the Senate or the nation. His actions are generally reflected the will of his caucus, and if it did not, his caucus would replace him. The same would be true if he were leading the Republican caucus.
I am not for a moment suggesting this would happen, but merely pointing out that it could, and that if Reid truly simply craves power, as many of his critics contend, it actually would work, and he would just as eagerly carry out the bidding of his new caucus as he has done with his current caucus.