Laws generally seen outside the U.S. Northeast
that forbid mandatory union membership
as a condition of employment
These laws are generally passed to promote job growth. Corporations are attracted by the ability to avoid collective bargaining as much as possible, and employees aren't forced to take deductions for union membership from their paychecks if they don't feel it necessary to join. This makes job relations somewhat complex in union shops, as non-union and union workers may be working side-by-side in the same job capacity, but have distinctly different career goals and relations with management.
deep thought: you're dead-on that this hasn't happened in Virginia -- most of the places that need the jobs (specifically, the far southwest, and Martinsville and Danville near the North Carolina border) have long traditions of heavy unionization. The BMW plant in Greer, SC and the Mercedes-Benz plant in Alabama are probably the most shining examples of the job growth phenomenon as a result of right-to-work.