Senator Joe Lieberman of Connecticut won’t be running for another term in Congress. Lieberman, whose political identity has morphed confusingly through the years—a Democrat who campaigned actively for a Republican presidential candidate, an “Independent Democrat” after he failed to win a Democratic primary, an Israeli sympathizer whom it would hardly be a joke to call AIPAC’s (American Israel Public Affairs Committee’s) man in Congress—is said to have seen his re-election chances as doubtful.

By now, that’s a tribute to the good sense of voters in Connecticut.

It wasn’t always so. From 1983 through 1988, Lieberman served as Connecticut’s attorney general, going after corporate polluters, chasing down deadbeat dads and fighting for consumers. When he unseated liberal Republican senator Lowell Weicker in 1989, people who had known him as Connecticut’s AG cheered the gutsy new Congressman with a refreshing sense of public service. In 1990 he co-sponsored the Clean Air Act, and his commitment to the environment has endured; he ran for vice-president on Al Gore’s ticket in 2000, and has continued to warn against global warming.

But from the mid-’90s Lieberman took positions that seemed inconsistent with other features of his politics and character. In 1995 he and Lynne Cheney, whose husband Dick Cheney would later become vice-president, founded a group called the American Council of Trustees and Alumni, or ACTA. Ostensibly formed to support “academic freedom” at public universities, ACTA in December, 2001 issued a report claiming that “colleges and university faculty have been the weak link in America’s response” to the attacks of September 11.

The so-called War on Terror, perhaps in combination with influences from his marriage to a daughter of Holocaust survivors, seemed to engender in Lieberman an obsession with the world as theater for the conflict between the American/Christian-Israeli bloc and the “jihadists” who threatened it.

It was because of that that he outraged Democrats by openly supporting hawkish John McCain in the presidential election of 2008, as well as supporting the drive for invading Iraq in 2003 and speaking so abrasively about Iran that General Wesley Clark once said, “Senator Lieberman must act more responsibly and tone down his threat machine.”

Mark Vogel, chairman of the pro-Israel National Action Committee, once said that Lieberman was “the No. 1 pro-Israel advocate and leader in Congress. There is nobody who does more on behalf of Israel than Joe Lieberman.” There’s a difference between taking positions on foreign policy and using the resources of the U.S. government to serve the interests of another country. Over time, the weight of Lieberman’s concerns, statements and actions have moved closer to the boundary between the two; in some cases—when he’s lobbed reckless threats at Iran, for example—they’ve been over the line.

And Robert Parry, a distinguished investigative reporter who broke the Iran-Contra story for the Associated Press, has speculated that Lieberman used the health care issue to pressure Obama not to demand deep concessions from Israel as the president tried to broker a plan for peace between Israel and the Palestinians.

When credible witnesses ask whether a Congressman cares as much about American interests as about the interests of a foreign country, it’s not a bad time for that Congressman to retire. Lieberman is a good man who might have been a better senator if a different set of national and global issues had arisen during his tenure. Now it’s time to thank him for his gift of help with the repeal of Don’t Ask, Don’t Tell and get ready to say goodbye.