Most reggae of the roots variety has at least a couple of songs that are political in nature. I love the shit, personally. Barrington, Don Carlos, Gregory Isaacs, Eek-A-Mouse, Freddie McGregor, Junior Reid,...I could go on for minute.
Oh, and that post Katrina Mos Def was called Katrina Klap. I would say every album he's cut has at least 3 jams on it that are political. My favorite has to be What's Beef?...
"Beef is oil prices and geo-politics,
Beef is Iraq, the West Bank and Gaza Strip,
Some beef is big and some beef is small,
but what y'all call beef is not beef at all,
beef is real life, happening everyday,
and it's realer than them songs that you gave to Kay Slay.."