I really don't disagree with you. I don't like it when candidates make promises they know they can't keep. The price they pay for using disingenuity to get elected is a short tenure in office once the public realizes their campaign rhetoric was just that - empty words.
Like it or not politicians will always weigh the costs of being too honest. If being honest will cost them an election they'll shrink from it. If lying will get them elected let the voters beware.
The primary responsibility for keeping politicians honest rests with the voting public. Sometimes the public doesn't pay much attention to campaign misinformation or chooses to accept what a candidate says on its face until after the election when events prove that the promises were empty. 
You can almost see an evolutionary arms race as candidates and the public recalibrate after each election. Candidates learn how to parse their words more carefully to maintain the appearance of honesty and the voters grow more sophisticated in judging the candidate's veracity. It could be an analog of predator/prey relationships as successful survivors pass on their genetic modications to new generations.
The danger in our political system is that the public can become cynical. God knows lots of people don't bother to vote. What was the last national voter turnout, 39 percent?
Its hard to be an idealist with so much cynicism going around and my column may just add to the cynicism. On the other hand, as Winston Churchill said, (and I paraphrase) Democracy is the worst form of government there is, except for all the others.  We are who we elect, and the choice is ours.
Pawlenty's no new taxes pledge is ridiculous at least under the circumstances. The idealist in me, the one that wants government to work is trying to promote an idea that will enable Pawlenty to back away from a stupid pledge that helped him get elected. Minnesota's future is in his hands and I don't want him to imperil the state just so he can tell everybody that, by golly, he kept his word.
This column opens me to the charge of being manipulative, and cynical. Well, yeah, I guess I am. I blame it all on Pandora. Fortunately the last thing that escaped from her box was hope. I'd like to think that my poor attempt to debunk the tax pledge will help us back away from it.