REDFORD, MI — President Barack Obama launched an assault Monday on Michigan's proposed “right to work” legislation, which would weaken unions in the state, saying the law is motivated by politics, not the economy.

“What we shouldn’t do — and I just have to say this — is try to take away your rights to bargain for better wages,” Obama said, as the crowd of invited guests, including many union members, roared.

Last week the Republican-controlled Michigan House and Senate passed the legislation, which would prevent workers from being forced to pay union dues as a condition of employment — a move to curb the influence of unions in the state.

Each chamber of the legislatures must now pass the other’s version of the bill, but the legislation is expected to reach the desk of Republican Gov. Rick Snyder as soon as this week. Democrats are organizing in the state to pressure him to veto it.

“These so-called ‘right to work’ laws don’t have anything to do with economics,” Obama said. “They have to do with politics. What they are really doing is giving you the right to work for less money."

“We don’t want a race to the bottom — we want a race to the top,” he added.

Speaking on the fiscal cliff outside Detroit at a truck-engine manufacturing plant, Obama said the United States doesn’t want to compete in an economy of jobs with “low skill, low wage, no workers’ rights.”