Sen. Bernie Sanders on Monday told a gathering of union machinists that as president he would keep states from undermining their rights by pushing for a federal ban on so-called "right-to-work" laws.

Calling the rules "disastrous," Sanders told the International Association of Machinists that he would call on lawmakers to pass the Workplace Democracy Act, a proposal which he has regularly introduced in Congress since 1992 and which he plans to bring to the Senate floor once again in the coming days.

Under "the most significant labor legislation introduced in very, very long time...we will end once and for all the disastrous right-to-work laws in 28 states," Sanders said to loud applause.

The senator and 2020 presidential candidate also said the law would keep companies from "ruthlessly exploiting their employees by misclassifying them as independent contractors and [denying] them overtime by calling them supervisors"—both common practices by corporations.

Under right-to-work laws, unions are barred from requiring that all workers contribute dues if they benefit from the union's contract. The laws have been aggressively pushed by Republican governors and lawmakers in recent years, with proponents claiming they protect workers from being forced to join a union.

"The reality is that federal law already makes it illegal to force someone to join a union," the AFL-CIO says. "The real purpose of right to work laws is to tilt the balance toward big corporations and further rig the system at the expense of working families. These laws make it harder for working people to form unions and collectively bargain for better wages, benefits, and working conditions."

At the machinists' association meeting in Las Vegas, Sanders also slammed recent actions by American Airlines as examples of corporate greed and how it's resulted in an increasingly weakened labor rights movement.

"Right now, American Airlines wants to slash the pay of its workers, outsource jobs, take away healthcare benefits, and abolish its defined benefit pension plan," Sanders said. "If you have enough money to buy back $15 billion of your own stocks, you damn well have enough money to pay your union workers a decent wage with good benefits. Go back to the negotiating table. Bargain in good faith. Treat your workers with the dignity and the respect they deserve."

The pro-Sanders grassroots group Bay Area for Bernie praised the senator for his strong support of union rights.

"We are in a blatant class war in the U.S. and we cannot win unless we as workers unite and unionize," the group tweeted. "Bernie knows this. And he will fight to make it happen."