On the Fourth of July, as we celebrate the freedoms that are fundamental to our national experience, we should also take a few moments to contemplate those denied such freedoms.

Modern-day slavery – sexual slavery or forced labor – affects almost 21 million people around the world. Pope Francis has called modern slavery a “crime against humanity that should be eradicated from the earth.”

During an election year, we are right to ask why such an important issue does not loom large on the political agenda. A simple answer: its victims do not vote. They live in the shadows with little protection from law enforcement, in fear for their lives. Over half of those trafficked are women and children. Many are forced into the sex trade. Thousands of them are in the United States.

The United States has led international governmental efforts to combat trafficking for nearly two decades, including through the Department of Labor’s Bureau of International Labor Affairs, known by the acronym ILAB. This bureau not only researches causes of child labor, slavery and human trafficking, but also combats some of their worst forms. The Senate Appropriations Committee was right to protect its funding in its recent appropriations markup.

ILAB funded the YouthBuilders project implemented by Catholic Relief Services and the local Catholic Church in Central America. YouthBuilders works with private-sector companies and regional governments to train thousands of youth and provide seed capital to create employment alternatives in the limited job market. Providing economic opportunity for young people reduces their vulnerabilities to exploitation.

We must keep at this work if we are to achieve the pope’s goal of eradicating slavery by 2020.

One critical step: Congress should pass the Business Supply Chain Transparency on Trafficking and Slavery Act (S. 1968, H.R. 3226). This legislation would require businesses with more than $100 million in receipts to report to the U.S. government about steps they take to ensure that no slave labor is used in their supply chains.

Such legislation would help to ease the consciences of consumers to know that they are not buying products created through forced labor.

We must all work to see that those enslaved or trafficked are not shunted to the shadows, but treated with the dignity and respect we would want if we were in their shoes.

The Statue of Liberty hails the freedoms which so many sought in the United States. With those freedoms comes responsibility. Let’s work to eliminate modern-day slavery and human trafficking so that millions can come out of the shadows to join us in the light of freedom.