Most Americans have never heard of David Obey, but in Washington, where he chairs the House Appropriations committee, he's the man to see. He holds the congressional purse strings, overseeing the dispersal of funds for everything from the Iraq War to those much-disparaged earmarks, the lifeblood of legislators. A serious and passionate legislator, his decision to retire at the end of this term is evoking yet another round of soul-searching on Capitol Hill about the tenor of American politics.