In an article entitled "Employee Free Choice Act and Republican Disinformation," Democratic Talk Radio Blog states:

If you distribute any union materials including union pledge cards on company property during working hours, you can and usually will be fired. . . .

. . . The Republicans and their large corporate masters are being completely dishonest in the way they frame the issue and describe the current situation.

Sorry to let the truth get in the way of a good argument, but the current law protects employees' rights to distribute materials on company property so long as it is done in non-working areas (such as breakrooms and parking lots) and on non-working time (such as breaks).   For a "completely honest" description of the "current situtation," read the U.S. Court of Appeals for the Sixth Circuit's decision in UPS v. NLRB by following this link.