He was one of the chamber's most important members, which explains why a nearly full-body-size portrait of former Sen. Mike Mansfield hangs in the Senate Mansfield Room. The elegantly appointed hall just off the Senate floor is host to the weekly Republican members' lunch. For over a decade, senators have dished up chow like last week's filet mignon and veggie lasagna from steam tables under the portrait. "It's always been that way," says one insider. Well, last week the food was moved to another wall. Reason: Years of rising steam have started to damage the painting by famed artist Aaron Shikler, known more for his JFK and Nancy Reagan works hanging in the White House.