Saying he needed to devote all of his time to running for mayor, Michael Nutter has resigned as chairman of the Pennsylvania Convention Center Authority board, where he won praise as a hardworking peacemaker after a tumultuous start in the position four years ago.

Nutter's resignation, which took place Tuesday but was not announced until yesterday, comes at a crucial time in the planned $700 million expansion of the 14-year-old center.

Nutter, a City Council member before quitting last year to go after the mayor's job, was deeply involved in negotiations with Gov. Rendell's office over the cost and management of the state-funded project.

Several other directors of the 14-member Convention Center board said they were surprised by the resignation. But the directors, all appointees of state, city or regional political leaders, said they did not expect Nutter's departure to delay the expansion or hamper it in any way.

Nutter said in his letter of resignation that he needed to spend the four weeks until the May 15 mayoral primary running for office.

"I do not want my campaign commitments to jeopardize the pace of our successful work on the expansion project and other key . . . initiatives," he said in the letter.

In an interview, Nutter said that he was not pressured to resign and that several board members asked him to reconsider. "This was totally my decision," he said. "It's because running for mayor is really a huge responsibility."

The expansion project, scheduled for completion near the end of 2009, will almost double the size of the Convention Center, extending it from 13th Street to Broad, between Arch and Race. The goal is to make the building more competitive with other big East Coast centers, including those in Boston, New York and Washington.

The Convention Center Authority staff started seeking contractors this week that it believes can run the massive construction project, asking them to show that they are qualified for the job before they will be allowed to submit formal bids this summer. The city Redevelopment Authority, which has acquired most of the land needed for the expansion, expects to award a contract in May for demolition of buildings in the way, agency spokesman Frank Keel said last week.

Nutter's successor will be chosen by the Convention Center board, but does not have to be one of its current members. One board member, who asked not to be identified, said he hoped the group could have "a unified approach," agreeing unanimously on the new chairman.

The board wants to avoid the same kind of bitter divisions that Nutter faced when he was elected chairman in early 2003, a few months after the state General Assembly adopted legislation that took control of the board away from the city and gave the legislature more power. Rendell and Mayor Street publicly opposed Nutter as chairman, but he had the support of key legislative leaders, including Rep. Dwight Evans, who is also a candidate in the Democratic primary for mayor.

Nutter was lauded by those he worked with at the Convention Center and the Philadelphia Convention and Visitors Bureau for being an energetic leader who played a key role in ending years of strife among the six labor unions that work in the building.

Albert Mezzaroba, president and chief executive officer of the center, said Nutter was rare among people in his position because the building's customers - the meeting planners who decide where to hold major conventions - knew who he was. "That's very important, because four years ago, our clients were gone, with the labor reputation so bad," he said.

One of those key customers, Deborah Richardt, director of meeting services for the American Thoracic Society, called Nutter "a rare gem in this industry.

"You do not find many politicians eagerly acting upon the suggestions of meeting planners," she said in a statement. "More than once, I saw firsthand our ideas being implemented thanks to Michael's leadership."

Inquirer staff writer Larry Eichel contributed to this article.
Contact staff writer Tom Belden at 215-854-2454 or tbelden@phillynews.com.