If the states win, there would be no direct impact on private-sector workers.
In 1991, 12 percent of private-sector workers were union members.
Passed in 1935, it established the legal right of private-sector workers to organize unions.
Today, about 44 million private-sector workers and retirees are covered by such plans.
For private-sector workers nationwide, as of 2011, the average is 10.7%.
Indeed, small business employs 60 percent of the nation's 99 million private-sector workers.
They might be required to pay some of the cost for health benefits, like private-sector workers.
In 1999, about 1.7 percent of private-sector workers received options, according to the most recent government study.
Today, only 8 percent of private-sector workers carry union cards.
Roughly half of all private-sector workers are employed by small businesses.