The misnamed "right to work" laws are based on an ideological sleight-of-hand. Union shop contracts are enforced not by unions but by employers, because it's their private ownership of the means of production that gives them the power (backed by the state's guns) to exclude people from social production. When they do so they are simply exercising exactly the same right as when they exclude someone -- i.e., decide not to hire them -- for any other reason (aside from those specifically excluded by law like "race" or gender). And they will do so whenever they've judged it's in their interests as capitalists to sign such contracts, just as when they exclude people on any other basis. Laws prohibiting such contracts don't create an actual right to work because they leave untouched the institution that actually stands in its way: capitalist private ownership of productive wealth.