Speaking out does have an effect.

I found this part in a larger article about the Budget from the Washington Post.

At least one Republican, Rep. Rob Simmons of Connecticut, has had a change of heart, thanks to laudable grass-roots pressure -- which, to his credit, Simmons acknowledged.

"I voted for it in December," Simmons said of the budget in a statement released last week. But after consulting with constituency groups, Simmons decided that the bill "remains unsatisfactory" and that "the budget, as it stands, falls short." Moderate Republicans who had no business voting for this bill in the first place should be challenged to join Simmons.

Now, I know one could say that he was a GOPer in a state that is liberal. However, if his constituents had stayed silent, chances are he would be voting for the upcoming budget bill.