7. Tommy Carcetti
It's hard not to like Tommy. He's a good guy (can stray away from his wife, but considering the other politicians we meet he's Ward Cleaver). We meet Carcetti in season 3, a young no non-sense City Counselman who is determined to change Baltimore. We follow him into his mayoral campaign, his first few years in office, and his realization that idealism won't get the job done. Carcetti is a great example of a (mostly) good guy who has great intentions but realizes that the system can't be changed by ideals. Thrown into a school budget crisis, a soaring crime rate, and a serial killer, Carcetti gets a crash course in politics and becomes everything he wanted to change in the first place. Ultimately, he throws his idealism out the window and slides into the same pattern as all of his predecessors. Juking the stats for political gain- and it works, at the end we see Carcetti making announcements from his new office in Annapolis.