Give a dog a bad name and hang him.
More Traditional Proverbs:
Many a man's nose was broken by his mouth.Traditional
The key to all problems is the problem of consciousness.
Traditional
Throw out a sprat to catch a mackerel.
Traditional
The world belongs to the shameless.
Traditional
When I want your opinion, I'll give it to you.
Traditional
A spur in the head is worth two in the heel.
Traditional