Most seats at the Federal level are not remotely competitive. For most seats in my area, get all the progressives to the polls for any candidate you pick and the results will be the same. The Dem or Repug will win as the seat was designed. Obama threw them a curveball in 2008 by getting "unlikely" voters to the polls in mass quantities. Even with that we barely unseated a couple of marginal wingers in congress who were replaced by true wingers in 2010.
The change in voter registrations left over from 2008 did cause them to throw Alan Grayson a seat for 2012. He now has a district where he should win by at least 5%, perhaps 10%. They did this to clean out the Dems from the other now much more secure winger Districts. A new equilibrium has been established, 3 wingers + Grayson. Run any candidates you like, mobilize whoever you wish, the results will be 3 wingers + Grayson. If you mobilize really well, the wingers will only win by 5 and Grayson will win by 15.
The larger point being that virtually no legislative career is made from issue advocacy, on either side really. The wingers promise to make all abortions illegal to get the fundy vote, but never actually do it, even when they hold all the cards. There is no point because if they make the fundys mad, they will only win re-election by 5 percent instead of the ususal 10 to 15. Only if the races become truly competitive will these folks begin listening to the voters. Short of that, they will only listen to the contributors.