The "Will of the People"

So many politicians are always saying things like, "The American people" want this, or "The American people" know what they want... Well, why are these same politicians so often dragging their feet, if not obstructing, legislative efforts that actually ARE demonstrably popular? The Buffett Rule is a great example: something in the range of 65-70% of people polled said they favor it. An even higher percentage say they're in favor of more progressive taxes in general. So what do "the American people" want, really, in the eyes of politicians? Apparently, "their" wants happen to correlate perfectly with most corporate and elite interests. Funny, that.