Editor’s note: David Abramowitz is Vice President, Policy & Government Relations for Humanity United and Director of the Alliance to End Slavery and Trafficking (ATEST), a coalition of U.S.-based human rights organizations working to end modern slavery and human trafficking in the United States and around the world. ATEST recently issued “The Path to Freedom,” a road map for the second-term Obama Administration to follow as it works to fulfill its commitment to eliminate modern slavery.

It’s been 150 years since President Lincoln’s Emancipation Proclamation declared in the midst of the U.S. Civil War that all slaves “shall be free.”

Today, the word “slavery” still conjures up horrifying images and stomach-churning thoughts about the most disgraceful days in U.S. history.

This shamefully evil chapter still cannot be fully explained, because no facts can possibly answer how humanity allowed it to happen, and why we didn’t stop it sooner.

Similar questions haunt the United States and countries around the world today – how has slavery evolved into a multi-billion dollar illicit global industry, overshadowed only by drugs?

Perhaps we turned a blind eye because modern slavery looks so different than it did in 1863, when it was largely in the open.

Modern-day slavery manifests itself in many new and nuanced forms, often described in the 21^st century as forced labor or human trafficking. Or perhaps we turned a blind eye because we can’t conceive how slavery can persist in 2013.

Human trafficking is viewed worldwide as morally reprehensible, and slavery is illegal in every country.

As a result, modern slavery is underground and masked so well that we may not recognize it in our own communities. For example, construction workers, housekeepers, farm workers and too many others in low-paying industries are brought to the United States by labor brokers who promised a job, but enslaved them instead.

Today’s slave is shackled by insurmountable debt, coercion, fear and intimidation. She has been lured into crossing a border or leaving home for what she believes is legal work, only to find herself trapped by an unscrupulous labor broker who seizes travel documents and threatens retribution by law enforcement or immigration authorities, or violence against family members if she leaves.

Slavery exists today for the same reason it did more than a century ago: money. The United Nations Office of Drugs and Crimes cites estimates that human trafficking in all its forms yields $32 billion dollars in profits every year.

That number may seem shockingly large at first glance, but is easily explained: the rise of globalization, demand for cheap labor, and supply of vulnerable workers. Massive, international companies use complex supply chains in order to, for example, deliver shrimp harvested in Thailand to markets in communities like Topeka, Kansas in a matter of days.

Most of the severe exploitation occurs at the bottom of these chains, where unpaid Burmese immigrants may be forced to stand in a shed for hours on end, peeling the shrimp we will enjoy days later at our dinner table.

The story varies tens of millions of times in a range of industries around the globe. You’ll find trafficking victims in the palm oil plantations of Malaysia and Indonesia, brothels of Phnom Penh, construction sites and homes in the Middle East and the suburbs of the United States.

So if we know that slavery and human trafficking exist today, how can we stop it?

There is no simple answer – trafficking and slavery are complex problems, encompassing human rights abuses, transnational crime, labor violations, humanitarian law, migration and immigration policy, sexual violence and child welfare. But that doesn’t mean there isn’t a solution.

The world’s business communities, governments and civil society must collaborate in order to create a comprehensive approach to the issue. For example, non-governmental organizations and law enforcement can reach out to communities to educate, help free victims, and advocate for and provide essential services to survivors.

The private sector can help ensure supply chains are free of human trafficking, forced labor and other forms of modern slavery, and that their employees do not personally reap the benefits of trafficking.

Philanthropic institutions can fund and produce new learning from path-breaking initiatives such as finding new ways to help victims make the transition to survivors, mapping supply chains and creating new tools to combat trafficking in supply chains, and cultivating technological approaches to combating trafficking.

And governments can ensure that they are not inadvertently involved in modern slavery, and institute and fund policies that can ultimately eliminate human rights crimes in individual countries.

In September, President Barack Obama announced several initiatives to fight modern slavery, including an executive order to strengthen U.S. policy on human trafficking in government contracting.

He also promised to provide relevant officials and agencies with training and guidance programs on human trafficking, and to expand resources and services for trafficking survivors.

Obama’s pledge to step up his administration’s efforts to combat modern slavery was significant.

Now, he must deliver on these promises, and his first priority must be working with Congress to reauthorize the Trafficking Victims Protection Act (TVPA) – the cornerstone of federal anti-trafficking efforts.

The TVPA has provided critical resources and new tools for those on the front lines in the fight against human trafficking and modern-day slavery, but was shamefully allowed to expire in 2011 due to political stagnation. Reauthorizing the TVPA is critical to maintaining U.S. leadership on this important issue.

As we honor the Emancipation Proclamation, the symbolic end to one of America’s darkest times, and observe January as National Slavery and Human Trafficking Prevention Month, I am hopeful that we are on the cusp of taking meaningful steps toward a modern emancipation.

Let us all ensure that, 150 years from now, our descendants do not ask why we allowed slavery to continue, and why we didn’t stop it sooner.