A member of the Maine Senate from 1991 to 1995, Summers ran for the Republican nomination for Maine's 1st congressional district in 1994, finishing second in the primary. He was the nominee for the same seat in 2004 and 2008, losing on each occasion to the Democratic candidate. From 2011 to 2013, he served as the Secretary of State of Maine. He was the Republican nominee for the U.S. Senate to succeed retiring Republican Olympia Snowe in the 2012 election, but lost to former independent Governor Angus King.