A new bridge connecting Windsor, Ont., and Detroit, Mich., has cleared another hurdle — but just barely.

The Michigan house narrowly passed legislation Wednesday that would let the state get involved in a project to build the new $6-billion US bridge.

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The current Ambassador Bridge stretches to Detroit, Mich., from Windsor, Ont. Canada wants to replace the Ambassador Bridge and has offered up to $550 million to cover costs of the project on the U.S. side. ((Rebecca Cook/Reuters))

The 56-51 vote is a partial victory for supporters of the proposed Detroit River International Crossing to connect Michigan and Ontario.

But it's unclear if the legislation will pass the Republican-led state Senate, which is the next step needed for the project to advance.

Canada wants the bridge and has offered up to $550 million to cover costs of the project on the U.S. side.

Backers say the bridge would improve international commerce.

The private owners of the nearby Ambassador Bridge oppose the project.

Michigan legislators face a deadline of this Tuesday to approve bills allowing the state to join the new project.

Transport and Infrastructure Minister John Baird travelled to Detroit in mid-May to present Canada's offer to lend the financially strapped state funds to speed up construction.

The private company — Detroit International Bridge Co. — has vowed to sue Canada under NAFTA, claiming Ottawa is trying to undermine it by coercing Michigan into building a new, competing span.

The company has said a new span would siphon off traffic from the Ambassador Bridge and bankrupt the firm.

It also disputes Ottawa's prediction that truck traffic will triple, and vehicle traffic more than double within 30 years.

The project to build a second bridge is expected to create 10,000 construction jobs over five years and 25,000 permanent jobs once it is complete.