A few years ago, a city hall gadfly in Philadelphia decided to measure the activism of the city council's 17 members. Over a three-month period, he kept track of how often they spoke at meetings and how many words they uttered for the record.

The winners in this last category, to no one's surprise, were a couple of council members who oppose Mayor John Street. They clocked in at about 87,000 words between them. At the other end of the spectrum was a Republican named Brian O'Neill, whose 918 words placed him next to last. In Philadelphia politics, 918 words over three months counts as monastic silence.

But that was then. O'Neill has been doing a lot more talking of late, ever since the convoluted maneuvering that typifies Philadelphia power politics suddenly made him--for the first time during 25 years in office--a force to reckon with.

O'Neill, 54, is by nature neither wordy nor forcible. Since 1979, he has quietly represented Northeast Philadelphia, a set of modest working-class neighborhoods in the city's far corner. As a Republican in an overwhelmingly Democratic town--even in his district, the most Republican in the city, Democrats hold almost a 2-to-1 registration advantage--he didn't have much choice but to focus on his constituents and leave the ambitious strategizing to others. "Being a member of the minority on Philadelphia city council, you don't have much say in regular times," says Larry Ceisler, a public relations consultant on local issues. "The only real power he had was on projects or initiatives in his own district."

To be sure, O'Neill was hardly shy about using that power. Northeast Philadelphia is full of civic associations, sports clubs, youth groups and others with strong opinions about what happens on their turf, and over the years, O'Neill has repeatedly gone to bat for them in negotiating with developers, the city and anyone else with designs on their territory. "If they're fair and reasonable in saying they don't want something," he says of his constituents, "I'll make sure it doesn't happen. Or at least I'll die trying."

But that all happened more or less below the public radar. For O'Neill to emerge into the limelight required a twist in the council's factional politics. At the beginning of this year, a faction allied with Mayor Street decided to force the council's chair, Anna Verna, to share power with them. Verna is closely associated with Street's opposition on the council. Because she is in her 70s and widely liked as a person, however, no one wanted to unseat her officially as chair. So a scheme was devised to make Verna seek approval of her actions from the council's majority leader, a Street loyalist. When those two disagree, the tie gets broken by the minority leader. That happens to be Brian O'Neill.

While O'Neill often votes with Street--"If there's something that doesn't involve my district that I don't feel strongly about, I usually side with the mayor," he says--the quiet Republican councilman has struck some highly visible blows against Street and in favor of the opposition. One issue O'Neill does feel strongly about is the city's tax burden on wages and businesses. He believes in cutting it. And in a long budget showdown, he helped lead the council to pass a cut in the wage tax and end the "business privilege" tax, which he contends makes Philadelphia uncompetitive. Street vetoed the business- tax cut, a move that O'Neill's faction failed by one vote to override.

Even so, O'Neill shows no signs that he's ready to return to his inconspicuous ways. The tax issue will resurface this fall, and O'Neill fully expects to be in the middle of it. "It's all got this minor--okay, very minor--Shakespearean play quality to it," says one veteran political analyst. "O'Neill gets this role and makes some assumptions about what he's going to do with it, and all the people who helped him get there appear to be surprised."