Here is a look at the landscape in some Rust Belt states that have pushed for right-to-work plans in recent years — some successfully, others not:
Illinois has not seen a serious right-to-work movement largely because of a near Democratic lock on the General Assembly in the past 30 years.
The Republican-controlled Legislature in Indiana approved right-to-work earlier this year. House Democrats walked out in 2011 for five weeks to block the measure by denying the GOP majority the numbers needed to conduct business.
The labor stronghold of Michigan became the 24th state to enact right-to-work on Tuesday when the House approved the final version of the legislation and Republican Gov. Rick Snyder signed it hours later.
Ohio voters in 2011 overwhelmingly rejected a sweeping law that placed restrictions on public employee unions. Republican Gov. John Kasich says making Ohio a right-to-work state is not among his priorities and that he sees other ways to keep the state competitive.
Pennsylvania labor unions have been largely successful in pushing back against efforts by first-term Republican Gov. Tom Corbett to dramatically scale back their gains. But Corbett says the state apparently lacks the political will to enact right to work.
Wisconsin's Republican-controlled Legislature in 2011 voted to pass Gov. Scott Walker's proposal that effectively ended collective bargaining for most public workers and forced them to pay more for health insurance and pension benefits. Walker argued it was a cost-saving move.