Adams taught law at the American Institute of Banking from 1954 to 1960, and served as United States Attorney for the Western District of Washington from 1961 to 1964.

[7] After resigning his Cabinet post on July 20, 1979, Adams resumed law practice, this time in Washington, D.C., where he was a lobbyist for CSX Corporation and other railroad carriers.

[citation needed] On November 4, 1986, Adams was elected to the U.S. Senate, narrowly defeating incumbent Republican Slade Gorton with 50.66% of the vote.

A former Democratic Party activist alleged that in the early 1970s, when Adams was serving in the House of Representatives, he invited her to a Seattle bar, where he drugged her with what he called "Vitamin C", after she recalled suffering from a cold.

[13] A young woman in her thirties told The Washingtonian that while she was seated to Adams's right at a formal luncheon shortly after she had taken a new job on Capitol Hill, he slid his hand under her skirt to the upper part of her thigh, whereupon she tried to move her leg away from him.

But already under the spotlight due to previously aired allegations that he drugged and molested a young female aide in 1987, a highly publicized matter in which no charges were brought, Adams was forced to drop out of his reelection campaign.

There was a list of senators and congressmen whom young women were told to keep away from, which included Adams, John Conyers, Ted Kennedy, Bob Packwood, Mel Reynolds, Gus Savage, and Strom Thurmond .