[carbocation]

Sure. In Baltimore, I witnessed debate prior to a vote on a highly contested bill (smoking ban). Several city council members gave a 'call count' of the # of constituents in favor vs the # opposed, and voted strictly in line with their constituents' preferences. I'm sure there are many documented instances of individual politicians doing this, although you can never strictly be sure that it's not just coincidence that their constituents are on the side of their big donors.