If you want to learn about politics in Seattle, sooner or later you come to John Fox. For almost 30 years, Fox has been coordinator of the Seattle Displacement Coalition, a loosely organized, marginally funded organization that advocates for the homeless and low-income tenants.

A square-jawed man with broad shoulders, intense blue eyes and a mind that seems to recall footnotes from ancient government reports, Fox, at 57 years old, has emerged as one of the city's most visible, controversial and durable activists. He led fights over downtown development that threatened old apartment buildings. He resisted expansion of the Washington State Convention and Trade Center. He criticized city spending in South Lake Union as a subsidy for Paul Allen. He criticizes the Seattle Housing Authority as going soft on its mission. He's a passionate advocate for city government - which already was spending $33.6 million on housing in 2006 - to do even more for the poor.

I've known a lot of activists. They tend to come and go, grow weary of playing the scold, and move on to comfortable jobs and better pay.  But Fox has stayed true to his beliefs, and I can't say he's mellowed.

In certain powerful circles, Fox is regarded as annoying - a stone on the road to economic development. In the 1980s, an executive with Cornerstone Development Co. complained that Fox practiced a form of blackmail - making life difficult until money was paid into low-income projects. More recently, a spokesman for Paul Allen blamed Fox's "misguided antics" as a reason why Seattle was struggling to become a "world-class city." Criticism of that sort doesn't bother Fox, who prefers hardball when it comes to politics. He unleashes verbal assaults on developers, public agencies and organizations he considers wrongheaded. He names names. In press releases and commentaries, he tells tales of greed, betrayals and corruption. Who can resist a press release titled "A Fishy Legislative Stew is Cooking Up at City Hall"?

That's how he gets attention. "You have to be aggressive and assertive," he says. "Sometimes you have to scream and be a thorn in the side just to get on the playing field." Reporters call him a go-to guy. Since 1990, The Seattle Times has mentioned Fox 135 times.

"What makes John somebody the media call is, he is passionate, he does his research and he digs up stuff that's useful to journalists," says Bob Young, a city hall reporter at The Seattle Times.

Fox isn't always on the mark. "He perceives unethical behavior that's not always there," says Young.

Is Fox effective? Fox thinks so. He ticks off a list of state laws and city ordinances he's helped get in place that provide protection for tenants. He describes millions of dollars that flowed into housing projects after lobbying in Olympia by the coalition. He says he helped lobby the housing authority to roll back a rent increase. He helped found Ravenna House, a shelter for young adults. The coalition claims its lawsuits and administrative challenges have helped preserve 1,000 units of low-income housing that otherwise would have been destroyed by development.

"If you didn't have someone like John in Seattle, we'd be much poorer for it," says Joe Martin, a board member of Fox's organization. Fox has some support in the community, too. When Young quotes Fox's skepticism of Allen's South Lake Union project, he always gets approving messages from readers.

Michael Nank, a spokesman for Paul Allen, gives a carefully measured comment that seems to suggest, without actually saying it, that Fox is a classic outside agitator: "As far as John Fox goes, he seems to care passionately about his agenda. We respect that. Although he doesn't live or work in South Lake Union or work directly with the community on neighborhood issues, he certainly carries strong opinions."

Tom Tierney, executive director of the Seattle Housing Authority, puts a sharper edge on his comment: "[Fox] has lost credibility with many policy makers... He says things that are untrue." (Fox and the Housing Authority cite conflicting statistics on the number of Seattle Housing Authority low-income units.)

I called Fox the other day, wanting to know more about the guy behind the press releases. We met a week later in the University District outside a three-story brick apartment building that looks like the slightly worn buildings that Fox has tried to protect from the wrecking ball. Across the alley a new building is under construction that will cast Fox's apartment in shadow, blocking his view of the Olympics. Naturally, Fox organized a group that won concessions from the developer.

Fox led me down a hallway and into his one-bedroom co-op, which was decorated with inexpensive furniture, posters and photos from his years of activism. With pride, he showed me a photo of a construction worker putting him in a headlock during a protest. I noticed a book about high school football in Texas, Friday Night Lights. Fox told me he had been a star quarterback at Meadowdale High School and had played for the Huskies during the Jim Owens era. He had wanted to become a pro football player, but drifted into activism as he studied political science. He co-founded the Displacement Coalition in 1977. For its first public event, it hosted a mayoral candidate debate between Charles Royer and Paul Schell.

A friend from that era, David Hodge, became president of Miami University. Another, Frank Chopp, became speaker of the Washington House of Representatives. But Fox took a different path. In 1984, the Seattle Post-Intelligencer reported that Fox earned $12,000 from the coalition. Today, he says he's paid $18,000 out of a total coalition budget of about $30,000. Most funding comes from church groups, foundations and individuals. His largest donation, about $7,000, came from the Low Income Housing Institute. Fox has no other income. His parents, both educators, helped him buy his co-op in 1991.

During the two hours we spent together, Fox talked about his continued fights. He talked about the 50,000 pages of City Hall memos he's obtained on South Lake Union. He talked about how the Seattle Housing Authority was cutting back on the number of people served by its remodeling of old public housing.

Fox had a million more stories to tell. I asked him if he was getting tired of it all.

"I'm not going away. I love what I'm doing," he said.

O. Casey Corr, a columnist for Washington CEO, once ran for the Seattle City Council.