Massachusetts Republican governor has replaced the chairman of the state labor committee in an effort to resolve a bitter contract dispute between the city and its police union before the July 26 Democratic National Convention (search).

Gov. Mitt Romney (search) named former district court Chief Justice Samuel Zoll to the job Thursday. Zoll replaces vice chairman Morris Horowitz, who has been serving as acting chairman since late last year when the previous leader died.

The appointment came hours after the labor committee ordered arbitration between the city and the Boston Police Patrolmen's Association (search), but refused to expedite the process.

Romney said Zoll could call another committee meeting as soon as Saturday to appoint an arbitrator and potentially complete the process before the convention, which police have threatened to disrupt with picketing at many outside events.

Zoll was sworn in by the governor Thursday afternoon and said his first task heading the state Joint Labor-Management Committee is to familiarize himself with the dispute.

Under the decision made by the committee earlier in the day, arbitration would have proceeded under the normal timetable, with no arbitrator appointed until late next week at the earliest, just days before the convention.

The decision pleased neither side. The city wanted expedited arbitration, which would lead to resolution before the convention, while the union has long opposed allowing an independent third party to usurp the power of its members to vote on their own contract.

"Picket lines cannot be a consideration during the Democratic National Convention by people who are sworn to protect the public," Romney said. "The focus of public safety must be exclusively on providing for the safety of our visitors and our citizens."

The police union, which has already disrupted construction at the convention site and deterred Democratic presidential candidate John Kerry of Massachusetts from speaking to a recent gathering of U.S. mayors, is entering its third year of working without a contract.

The city has offered an 11.9 percent raise over four years, while the union wants almost 17 percent.