On the birthday of Dr. Martin Luther King, Jr., many politicians will praise his legacy even as they act in ways that betray his ideals.

Yohuru Williams, a professor of history at Fairfield University in Connecticut, reminds us that Dr. King was a strong advocate of labor unions because he understood that they protect the rights of working people by demanding fair pay and safe working conditions.

I was a small speck in the crowd when Dr. King gave his famous “I Have a Dream” speech at the March on Washington in 1963. Most of the chartered buses that brought hundreds of thousands of supporters to hear Dr. King that day were sponsored by labor unions. The theme of the day was “Jobs and Justice.”

Williams writes:

“Teachers, then and now, invoked the legacy of the Civil Rights Movement and the words of Martin Luther King to support a deeper investment in America’s public schools including more robust budgets for instruction, greater interventions for English language learners, and fair compensation. Their appeals for politicians to live up to the spirit of the movement fail to move political leaders like Rahm Emmanuel and Michigan Governor Rick Snyder whose positions on high stakes testing, teachers unions, and insistence on school closures represent the most egregious form of historical amnesia concerning the continuing relevance of Dr. King’s message.”

As the U.S. Supreme Court prepares to decide a case intended to cripple labor unions, we know that Dr. King’s prophetic warnings will be weighed too. Will working people have a chance to get middle-class jobs, or will they be stripped of any job protections, left to work at the whim of faceless corporations and heartless politicians?

Let it not be forgotten why Dr. King was in Memphis when he was murdered. He was there to advocate for the right of sanitation workers to form a union.