I think I know the theme of this year's U.S. Senate and House campaigns...at least as far as one political party is concerned.
Republican candidates are saying "I won't be a 'rubber-stamp' for President Obama/Nancy Pelosi/Harry Reid". John Raese has hammered it in his campaign ads...and other Republicans are claiming Governor Joe Manchin will only tow the Democratic line if they're elected to the seat long held by the late Robert C. Byrd.
The same is true in the U.S. House election. Republican David McKinley's campaign has, since the May primary ended, been putting out news releases claiming Democrat Mike Oliverio will only vote the Democratic line if he's elected to the first district congressional seat.
I didn't see any of these candidates (and Raese was Byrd's opponent in 2006) denying they would vote with then-President Bush on his goals. It all depends on which party they represent and which voters they're trying to attract to their side.
Some representatives in Congress have occasionally voted opposite of their party's wishes. Ohioan George Voinovich, who is retiring from the Senate after this year, has done so a few times. But largely, Democrats have voted with their party and the same is true with Republicans.
The only reason it's an issue this year is because of major differences, sometimes even within the two parties, on issues like health care and government stimulus/spending programs. Voters will support whichever candidate most closely votes in accordance with their own views, no matter what.
But it's an outcry you will probably see until this year's elections are resolved. And by then, you'll probably be sick of hearing about it.