OpenSecrets.org is a nonpartisan website that provides financial statements of Congressmen, Senators, and even lobbyists. They even monitor travel expenses and popular political destinations. If you're curious how much your representative is making and where his or her money is invested then take a look. You have the right to know.
http://www.opensecrets.orgOh course the smart politicians figured out ways of hiding their "questionable dealings" a long time ago, but the website is a great starting point and you could easily spend hours following the paper trails.
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