He is neither a politician nor a union leader.

But the reaction of one veteran carpenter to a City Council proposal last Thursday that would permit nonunion contractors to bid on jobs at the Convention Center cut to the heart of the matter.

"What are they trying to do, commit political suicide?" he said of the Council members who supported the resolution.

And of the potential response by others in the building trades, he added, "The unions can't get along with each other down there. How do you think they're going to react to nonunion workers?"

The carpenter, because of his union ties and his continuing desire to work, would speak only anonymously.

Both his questions hung in the air Friday, the day after City Council members, upset with Building Trades Council leader Patrick Gillespie's failure to provide data about the number of minority members and women working in the trades, introduced a resolution that would open Convention Center contracts to nonunion companies.

The resolution still needs to be approved by Council. And even then, it would have little effect unless Gov. Rendell and members of the Convention Center board went along.

The conventional wisdom in political and government circles last week was that that won't happen.

But the mere fact that it has become part of a public debate raises questions about an alliance that has defined politics and power in Philadelphia for generations.

Organized labor and the Democratic Party have always been in bed together. As a result, Philadelphia has long been perceived as one big union shop.

Contractors who ignored that fact did so at their peril.

One of the most enduring images of the Philadelphia Building and Construction Trades Council is now more than 35 years old.

On June 5, 1972, about 1,000 members, many wearing hardhats, swarmed over a construction site in Center Square, Montgomery County, where nonunion contractor J. Leon Altemose was building the Valley Forge Sheraton Hotel.

The union members "stormed the Valley Forge site, overrunning a fence and destroying $400,000 worth of equipment and materials," according to a Pennsylvania Crime Commission report on the incident.

"The half dozen or so local and state police were helpless in the face of the mob, and the Altemose security guards fled for their safety," the report said.

Despite the criminal charges that followed and the conviction of at least 11 of the participants, the Altemose siege remains a point of honor for many in the macho world of the building trades.

A lot has changed in 35 years.

The kind of wanton violence that surrounded the Altemose affair - Altemose was assaulted in a related incident - has largely been replaced by pickets and political posturing.

But union jobs are still something the trades council is willing to take to the streets for. A threat to jobs at the Convention Center - where the work is considered some of the cushiest and best paying (when overtime is taken into account) in the industry - would be a call to action.

Consider two incidents in which much less was at stake:

Ten years after the Altemose fracas, 2,500 members of the building trades turned out to protest a decision by Sun Co. to use a nonunion contractor to do routine overhaul work at a Marcus Hook refinery. The union members, many of whom walked off other jobs to join the rally, blocked traffic on 18th Street near the Sun Co. office on Market Street for several hours to make their point.

And just two years ago, 1,000 members shut down Kelly Drive and Ridge Avenue because an East Falls apartment complex expansion project there was being handled by nonunion workers.

More often than not, the city has backed the unions.

The Zoning Board of Adjustment, for example, entered the apartment complex dispute.

The board's solicitor filed a complaint against the developer, pointing out that a variance for the work was granted only after the out-of-state contractor had committed to using union labor.

That kind of support has long been considered a given, part of the unspoken political quid-pro-quo that defined the relationship between the unions and the Democrat Party.

In exchange, elected officials - including members of Council - have counted on labor unions for political contributions and for help in getting out the vote on election day.

Last week's Council action was a dramatic departure from the status quo and raised the question: Are Council members ready to risk that support?

"There have been rifts in the past," said former City Democratic Party Chairman David Glancey last week. "Labor and the Democratic City Council members have come down on different sides of issues."

But rarely, Glancey said, have those disputes been the subject of public debate and a potential Council vote.

"Any time it goes public, it makes the chasm grow wider," Glancey said.

Adding to the political equation is the recent election of Michael Nutter as mayor.

Nutter had little support from organized labor, yet managed to wrest the Democratic Party nomination from other candidates who did. He then coasted to a general election victory last month.

Has his success emboldened Council members?

That was part of the buzz on Friday at the annual Pennsylvania Society soiree at the posh Waldorf-Astoria in New York City.

"Sometimes, especially at the end of sessions, people feel a little freer and can be more reactive because they know a new administration is coming," said Larry Ceisler, a Democratic political consultant whose clients include trade unions.

Nonetheless, Ceisler said, he was "surprised" by the resolution.

"A majority of City Council has been elected with union support and understand fully what the trades union agenda is," he said. "I know in the case of several unions they've really tried to expand their minority membership, and I know Council members are aware of that."

In fact, there are those who believe the current dispute has as much to do with race as it does with labor.

African Americans and Latinos are still struggling to find a place in many of the building trades - indeed, the failure to establish meaningful doorways into the trades is at the heart of the dispute.

But those same groups are without question a powerful bloc that recent history has shown can deliver the votes needed to win elections in the city.

That is the role that organized labor traditionally has played for the Democratic Party.

Contact staff writer George Anastasia at 856-779-3846 or ganastasia@phillynews.com.

Inquirer staff writer Marcia Gelbart contributed to this article.