Thousands protest against labour Bill

Republicans hold a majority in the Michigan House so the debate was, at best, one-sided.

But outside the House opinion ran very much the other way as protesters continued to arrive throughout the day and, because the Capitol shut its doors when it reached capacity, nearly 10,000 union members massed on the building's lawn.

Streets around the Capitol were closed to traffic and nervous groups of state police, some carrying riot gear, congregated in nearby roads.

Two school districts announced that they would close for the day as teachers and other staff headed for the protest in Lansing.

President Obama denounced the measures on Monday, as have the state's opposition Democrat leaders.

But Republicans insist on backing legislation announced last week that would bar workers from being required to pay union fees as a condition of employment - in essence banning the previously recognised closed shop.

"You know, these so-called right-to-work laws, they don't have to do with economics," said Mr Obama during a visit to a car factory outside Detroit.

"They have everything to do with politics.

"What they're really talking about is giving you the right to work for less money."

The House will eventually have to vote on two measures - one dealing with employees at private companies, the other with public-sector workers.

Last month Democrats asked voters to write collective bargaining into the state constitution.

But that ballot failed badly and backfired, so now the base of the United Automobile Workers finds itself becoming the 24th state to ban the losed shop.

Labour leaders have long complained that the state was harming unions by trying to prevent school districts deducting dues at source and allowing state-appointed managers to reject union contracts.

And the latest legislation has confirmed their opinion.

UAW president Bob King said he believed that the governor had been "overwhelmed by pressure from right-wing sources."