What effect did the Taft$-$Hartley Act of $1947$ have on the U$.$S workforce?

The Act

gave states the power to let workers decide whether or not they wanted to join a union if the workplace already had a union.

set up the National Labor Relations Board for settling disputes between the union and management.

forbade the hiring of undocumented immigrants and required proof of citizenship as part of employment.

gave workers the right to have $60-$days notice for plant closings or large layoffs if the firm had more than $100$ employees.