CBS News recently reported the number of illegal immigrants in the U.S. is down by about one million from 2008 to 2009. The DHS report CBS cited also shows a striking difference in the number of illegal immigrants entering the U.S. in two different periods. From 2000 through 2004, 28 percent of the current population of illegal immigrants entered the United States, and only 8 percent entered from 2005 through 2008.

Having worked with these DHS statistics for a number of years, I am keenly aware of their limitations. I suspect the economy has played a role in this decrease, but I also think we need to give some credit to improved border enforcement and particularly to a little heralded but successful effort to end “catch and release.”

I was fortunate enough to help lead a team to develop the initial concepts of the Secure Border Initiative (SBI) and to re-engineer the removal process. The project’s success was a result of improved efficiencies and the considerable deterrent effect of migrants no longer being routinely released into society.

Recall the situation in the summer of 2005: The effectiveness of U.S. border control was under fire. A million illegal immigrants per year were streaming across the southern border, and tens of thousands were making their way across the northern border. The U.S. Border Patrol was interdicting only a fraction of the flow, most of whom were Mexican and were simply returned across the border where they could once again attempt the crossing. In addition, several hundred thousand “other than Mexicans” (OTMs) were also interdicted. These OTM could not be returned to Mexico; they were processed in the immigration court system, released and told to return for a hearing several weeks or months later.

This process was known as “catch and release.” Beyond the problems with “catch and release,” there were tens (if not hundreds) of thousands of “overstays.” These were people who entered the U.S. legally but overstayed their visas. Criticism was also mounting about illegal immigrants taking jobs and displacing American workers. Stories about deplorable conditions in detention facilities, and the administration’s lack of understanding of how much money they were spending and where they were spending it, fueled more public frustrations and led to the common perception of a broken border control system.

It was against this backdrop that then-DHS Secretary Michael Chertoff vowed to fix the problem. Effective border control became the sine qua non of comprehensive immigration reform. The strategy to control the border became known as the Secure Border Initiative (SBI). Although SBI was originally envisioned to include measures to attack the problem on a number of fronts, including at ports of entry, along open border spaces between ports of entry, and in the country’s interior. Secretary Chertoff quickly realized that the call for enforcement measures, specifically more Border Patrol Agents, was futile if more agents apprehended a greater number of illegal immigrants only to return them across the border or release them into the community.

Immigration and Customs Enforcement, who managed the detention and removal process, estimated that to stop “catch and release” they would need to increase the number of detention beds from about 20,000 to well over 120,000. This increase in bed space would have cost about $3.6 billion.

The thoughtful, technocratic process of re-engineering the removal system did what one would expect – improve efficiency, reduce cost, and simplify the process. As a result of the removal re-engineering process, Secretary Chertoff was able to end “catch and release” within 10 months and with an increase of less than 10,000 beds.

There are any number of “systems” in the homeland security arena that would benefit from this type of rigorous analysis followed by clear decisions and determined implementation. I hope we see a few of these efforts this year.