Now, I am neither a Republican or a Democrat, but to answer your question, I would say the polls are coming back to reality. Every year people say they hate Congress, but over and over again they always vote back in "their" Congressmen so what does that really say. Maybe it is the fact that many of the Republican candidates are on the fringe (ie Tea Party) and the general election is always about being moderate since the whole country is actually moderate. This is just my opinion.
Have a great day :)