A quote from Pres. Biden:
“The choice to join a union is up to the workers — full stop. [in the USA]
Today and over the next few days and weeks workers in Alabama and all across America are voting on whether to organize a union in their workplace. This is vitally important — a vitally important choice. And there should be no intimidation, no coercion, no threats, no anti-union propaganda.”
There are federal laws that require employers to acknowledge their employees’ rights to unionize. See National Labor Relations Board:
https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/employees/your-right-to-form-a-union