If you don't like a law, contact your representatives and senators, and try to explain to them what the problems are with the proposed law.

The important things to remember is that most politicians are like executive level managers -- they have no idea what the edge cases are* -- what sort of false negatives or false positives it will get, what the other implications are, how people can get around it, etc.

A bit of searching will reveal tips when writing congress. I'd suggest that you not use form letters, and that you spend the money for snail mailing it -- a pile of paper complaints is more impressive than a bunch of emails. If you can't be bothered to spend a little bit of time on the issue, then it's probably not that important to you.

Oh -- and it was mentioned in the page of tips I linked to -- suggest alternatives. Don't just say it's a bad idea -- either describe the impact, and explain that no action is a better choice, or give another solution to the percieved problem.

Update: and don't forget the address. Make sure they know you're in their district, and that you're elligible to vote for or against them.

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* I'm active in my town politics. Last year, someone proposed to change the law regarding 'itinerant merchants' to ban them from the residential sections, not just the commercial district. I raised the issue that the current wording would affect girl scouts selling cookies and tupperware parties. They provided a specific exemption for 'house sales party', and changed the wording to not affect girl scouts.