Sen.Bernie Sanders (I-VT) wants the U.S. government to only provide federal contracts to trucking companies that pay workers a living wage and benefits, he stated in a letter President Trump last week.

In the letter, he cites a controversial USA Today report that described the plight of certain independent-contractor drivers working at the Ports of Los Angeles and Long Beach who worked to pay off truck leases and took home little pay. Sanders urged President Trump to sign an executive order that would deny government contracts and subcontracts for trucking companies that misclassify workers as independent contractors, force workers to lease the trucks they drive, and engage in abusive labor practices.

Sanders also suggested that the Labor Department audit its current contracts and subcontracts awarded to port trucking companies to ensure they are in compliance with the wage and labor requirements of the McNamara – O’Hara Service Contract Act.

“This should not be happening in the United States of America,” Sanders states in the letter. “Truck drivers are the backbone of the American economy. They deserve to be treated with respect and dignity, not like modern-day indentured servants.”

Democrats on Capitol Hill have given extra attention to alleged labor and wage abuses at America’s ports since the USA Today expose ran earlier this year. In late October, Rep. Grace Napolitano (D-CA) and Rep. Jerry Nadler (D-NY) introduced two bills aimed at addressing labor and environmental issues at the ports.

However, port trucking companies and stakeholders have maintained that the cases outlined in the USA Today story were too extreme and not representative of industry practices.

They’ve also characterized it as part of an attempt to unionize labor at the ports by the Teamsters Union. The union has organized several driver strikes at ports over the past few years to protest what it says is a misclassification of drivers as independent contractors in order to forego paying proper wages and benefits.