Many states and local governments are considering right-to-work laws. These laws make union dues voluntary. Without them, union contracts make paying dues a condition of employment.

While most Americans support the concept of right-to-work, unions argue strenuously against them. However, most of the arguments against right-to-work have little basis in fact.

Myth: Right-to-work laws prohibit unions.

Fact: Right-to-work laws make union dues voluntary. Without right-to-work laws, unions negotiate contracts that force workers to pay dues or get fired. Right-to-work laws protect workers' freedom. The National Labor Relations Act also protects the right of workers in right-to-work states to unionize. Unions currently represent 4.4 million workers in 24 right-to-work states, including highly unionized Nevada, Iowa and Michigan.

Myth: Right-to-work laws undermine unions.

Fact: Right-to-work laws make unions work to earn workers' support. In the long run, this can strengthen union locals. Without right-to-work laws, unions can take their members' dues for granted and provide lower quality representation. Gary Casteel, the Southern region director for the United Auto Workers, explains:

"This is something I've never understood - that people think right to work hurts unions. To me, it helps them. You don't have to belong if you don't want to. So if I go to an organizing drive, I can tell these workers, 'If you don't like this arrangement, you don't have to belong.' Versus, 'If we get 50 percent of you, then all of you have to belong, whether you like to or not.' I don't even like the way that sounds, because it's a voluntary system, and if you don't think the system's earning its keep, then you don't have to pay."

Myth: Right-to-work laws allow nonunion members to "free ride" on the benefits of union representation without paying its cost.

Fact: Unions voluntarily represent non-members. The Supreme Court has repeatedly ruled that the National Labor Relations Act allows unions to negotiate contracts covering only dues-paying members. As Justice Brennan wrote in Retail Clerks v. Dry Lion Goods (1962), "Members only' contracts have long been recognized." Unions represent non-members only when they act as "exclusive bargaining representatives," which requires non-members to accept the union's representation.

In that case, the law requires unions to represent non-members fairly. They cannot negotiate high wages for their supporters and the minimum wage for non-members. Unions can avoid representing non-members by disclaiming exclusive representative status.

Myth: Representing non-members costs exclusive representative unions a lot of money.

Fact: Unions often spend little on representational activities. When unions choose to act as exclusive bargaining representatives, they often spend relatively little on processing grievances and negotiating contracts. Often union contracts have employers cover these costs by allowing union stewards to do union business while on company time. As a result, many union locals spend very little representing workers - either members or non-members.

Federal filings reveal that in 2013 United Auto Workers Local 2164 in Bowling Green, Kentucky, spent just 2 percent of its $560,000 budget on representational activities. Boilermakers Local 107 in Brookfield, Wisconsin, spent 5 percent of its $2.0 million budget on representational activities. Machinists Lodge 2515 in Alamogordo, N.M., spent 23 percent of its $645,000 budget on representational activities, almost all of which constituted payments to its officers.

Myth: Right-to-work laws provide no economic benefits.

Fact: Companies consider right-to-work laws a major factor when deciding where to locate. Organizing victories bring in a lot more money for a union in jurisdictions with compulsory dues. Consequently, unions organize more aggressively in places without right-to-work laws.

Companies in turn want to know they can avoid being targeted by union organizers if they treat their workers well. Right-to-work laws make that more likely.

Economic development consultants report that roughly half of all major businesses refuse to consider locating in jurisdictions with compulsory dues. Bureau of Labor Statistics data show that between 1990 and 2014 total employment grew more than twice as fast in right-to-work states as in states with compulsory dues.

Myth: Right-to-work laws lower wages.

Fact: Workers have the same or higher buying power in right-to-work states. Opponents often deride voluntary dues as "right-to-work for less." Average wages in right-to-work states are indeed slightly lower than in non-right-to-work states. This occurs because almost every Southern state has a right-to-work law, and the South has a lower cost of living. Studies that control for differences in costs of living find workers in states with voluntary dues have no lower - and possibly slightly higher - real wages than workers in states with compulsory dues.

 - James Sherk is Senior Policy Analyst in Labor Economics at The Heritage Foundation.