Now in his fourth term, Durbin is the second-longest-serving U.S. senator in Illinois history. The liberal lion enters 2016 with a few choice items on his bucket list—stricter gun control as well as immigration, criminal justice, and higher-ed reforms—and plenty of fire in his belly. Many political oddsmakers bet on the Democrats recapturing the Senate this year; Durbin, now the No. 2 Dem, has said that he won’t seek the top job. He could shake up some races nevertheless: He’s throwing his considerable clout behind his protégée Tammy Duckworth.