Louis P. Masur writes: In a speech delivered in September at the Clinton Global Initiative, President Obama declared that the time had come to call human trafficking by its rightful name: modern slavery. “The bitter truth is that trafficking also goes on right here, in the United States,” he declared. “It’s the migrant worker unable to pay off the debt to his trafficker. The man, lured here with the promise of a job, his documents then taken, and forced to work endless hours in a kitchen. The teenage girl, beaten, forced to walk the streets. This should not be happening in the United States of America.”

That same month the president signed an executive order that stated the United States would “lead by example” and take steps to ensure that federal contracts are not awarded to companies or nations implicated in trafficking. “We’re making clear that American tax dollars must never, ever be used to support the trafficking of human beings,” he said.

Still, the invisibility of modern slavery makes it all the more pernicious and difficult to eradicate. The organization Slavery Footprint asks on its Web site, “How many slaves work for you?” A survey poses a series of seemingly innocuous questions such as what do you eat, what do you wear, what medicine do you take, and what electronics do you use? Upon completion, a number is revealed: I discovered that 60 slaves work for me — cutting the tropical wood for my furniture, harvesting the Central Asian cotton in my shirts or mining the African precious metals used in my electronics.