That's kind of an ethical question. Practically, it seems to be smart, as it works to get into office...and the people's memory seems to be pretty short, so by the time you come up for reelection, the sheeple have forgotten about whatever it was you promised last time.
Look at Gov. Schwarzenegger. He ran on the illegal alien drivers' license issue. After just more than two months in office, he's already flip-flopping on it.