If politics is an addiction, Gavin Newsom needs an intervention.

A few weeks after telling the New York Times’ Maureen Dowd that he was ready to finish his term as mayor of San Francisco and become “the clerk in a wine store,” Newsom was talking Tuesday about a run for lieutenant governor.

“I’m considering it,” he said in a City Hall news conference, admitting that a campaign for the office is a serious possibility.

This is the same Newsom who spent a year running for the Democratic nomination for governor, then dropped out last October, citing his responsibilities as a husband, father and mayor.

The decision was “made with the best intentions for my wife, my daughter, the residents of the city and county of San Francisco and California Democrats,” he said.

Not to mention that he was out of money and falling far behind Attorney General Jerry Brown in the polls.

Less than a week before his abrupt departure from the governor’s race, Newsom was telling anyone who would listen that no way, no how was he going to be running for lieutenant governor.

Garry South, his chief consultant, had even earlier brushed aside the possibility that Newsom would run for a second-tier job like lieutenant governor.

“I’ve run a campaign for California lieutenant governor and served as the lieutenant governor’s chief of staff,” said the former Gray Davis aide. “I would have Newsom kidnapped by one-eyed aliens from Pluto if I ever thought he would make that decision.”

As an aside, South appears to have gotten over his unhappiness with the political potential of the LG job, since he’s now chief strategist for L.A. Councilwoman Janice Hahn, who’s running for that job. And no, South’s time with Newsom didn’t make his campaign resume.

But a poll earlier this month showing Newsom with a solid lead over both Hahn and Central Valley state Sen. Dean Florez got the mayor thinking. And Newsom is someone who does his thinking out loud.

There’s probably no politician in California who reveals as much of himself to the press and the public as the San Francisco mayor. When he told reporters Tuesday that he hadn’t made up his mind about a new run for office, you could believe him, since he seemed to be using the news conference to weigh his choices even as the cameras rolled.

His family and his job as mayor are important to him and that was the real reason he left the governor’s race, he said, but on the other hand, he hears the clock ticking on his political career.

“I love public policy,” he admitted. “I’m termed out, my days here are numbered as mayor.”

In his interview with Dowd, Newsom was flip and caustic, accented with a tinge of bitterness and self-pity.

Despite being an instantly recognizable figure, both in California and beyond, he’d be content to ride off into the political sunset at the age of 42, the mayor declared.

“This is it. God bless. It was fun while it lasted,” Newsom said. “Guys like me don’t necessarily progress very far, which is fine.”

But even before the ink was dry on the interview, Newsom was saying he wasn’t really serious.

“Don’t take it literally, is my point,” he told the San Francisco Chronicle.

That’s no surprise, because politicians don’t “go gently into that good night.” They typically leave kicking and screaming in one final election or, in this era of term limits, stay on the prowl for the next open seat.

That’s why Sen. Dianne Feinstein, at age 77, is raising money for a 2012 re-election bid. Or why Karen Bass is expected to seek the Los Angeles congressional seat Diane Watson is giving up. Or why so many termed-out legislators want to be attorney general.

At Newsom’s news conference you could see him struggle with a head that’s telling him a run for lieutenant governor might not be such a great idea and a heart telling him “go for it.”

Guess which side is winning?

“I believe I have something to offer” in a continuing political career, Newsom said. “I’d hate to just end it.”

John Wildermuth is a longtime writer on California politics.