Jackson first ran for the Maine House of Representatives in 2000 for Maine House District 151, as a Republican, and lost to Marc E. Michaud, Democrat. He was elected to House 151 in 2002 as an Independent, defeating incumbent Marc E. Michaud, Democrat. in 2004, after Maine's post census legislative redistricting, Jackson won a resounding reelection for House District 1, against Paul Berube, 3,486 to 1,248 In 2008 Jackson ran and won Maine State Senate District 35. In December 2012, Jackson was elected Assistant Majority Leader of the State Senate after the Democrats took back control of the body. On July 10, 2013, Jackson was elected Majority Leader of the Maine Senate after the resignation of fellow Democrat Seth Goodall. On July 1, 2013, following incumbent Democratic Congressman Mike Michaud's decision to explore running for Governor of Maine, Jackson announced he would run for Maine's 2nd congressional district, which had been Michaud's seat since 2003. On June 10, 2014, Jackson lost the primary to fellow State Senator Emily Cain. On Jan. 25, 2015, Jackson was elected as a member of the Democratic National Committee.. In November 2016, Jackson was re-elected to the Senate and a week later he was chosen by his fellow Democrats to be the Senate Minority Leader. During the 2016 presidential election, Jackson was a prominent supporter of U.S. Senator from Vermont Bernie Sanders' campaign and cast his superdelegate vote for him at the 2016 Democratic National Convention. He was chosen to introduce Sanders at a campaign rally before 8,000 supporters in Portland, Maine on July 6, 2015. During the 2020 presidential election, Jackson again supported Sanders, and again addressed a Portland rally for Sanders on September 1, 2019.
Politics
He is an advocate for health care and workers rights, especially for fellow loggers. In 2010, Jackson wrote a bill which would have "prohibited the Maine Department of Conservation from employing foreign laborers at state-owned logging sites". It passed both the House of Representatives and the State Senate before being vetoed by Governor Paul LePage. LePage questioned the bill's constitutionality while Jackson said that LePage was favoring large Canadian logging corporations over American workers. In June 2013, Jackson called LePage "obstructionist" and "delusional" regarding discussions about the 2013-2014 state budget. LePage responded by saying that Jackson "claims to be for the people but he’s the first one to give it to the people without providing Vaseline", as well as saying Jackson had a "black heart".