Why have the immigrant caravans marching toward our southern border stopped? In large measure it's because Washington started imposing consequences on those who flouted both international and U.S. immigration law.

The lesson is clear: Enforcing immigration laws deters illegal behavior.

That lesson should also be applied to illegal immigrants already in the U.S.—including DACA (Deferred Action for Childhood Arrivals) recipients. Lawmakers seeking to give green cards to those here illegally have not learned that lesson. If they prevail, they will end up encouraging another tide of illegal immigration.

The Trump administration’s decision to rescind DACA has been challenged, and the U.S. Supreme Court is expected to issue its decision this summer. What will happen to DACA recipients then?

If the court finds DACA to be lawful, DACA recipients  would retain their status of deferred action from removal (with work authorization), but they still would not have lawful or permanent resident status.

If, as is more likely the case, the court holds that DACA was unlawful, DACA recipients  would presumably lose both their work authorization and their “deferred action” status. Their immigration status would automatically revert to unlawful.

In either scenario, providing DACA recipients with lawful permanent status would require an act of Congress—something now under discussion in Washington.

Many argue that so-called Dreamers should be exempted from immigration law because they were mere children, brought here illegally by their parents. It would be cruel, they say, to deport them to a country they don’t even remember.

But relatively few Dreamers were babes in arms when entering the country. Many were teenagers, according to Department of Homeland Security data. When DACA was implemented, it covered those who entered the U.S. before their 16^th birthday and were no older than 30 by June 2012. The largest numbers of DACA recipients are now 21-35 years old, which would have made them 13-27 years old in 2012, when the program was announced. Further, most are fluent in the language of their native countries.

All Dreamers, however, have one thing in common: They are unlawfully present in this country. Offering amnesty to them—or any other group here illegally—would only encourage more illegal immigration.

The U.S. Border Patrol apprehension numbers clearly show that the Obama administration’s June 2012 announcement of DACA was absolutely a pull factor for illegal aliens coming to the U.S., whether as unaccompanied minors or as family units. The Border Patrol apprehended 16,000 unaccompanied minors in fiscal year 2011. That number increased to over 24,000 in FY 2012, almost 39,000 in FY 2013, over 68,500 in FY 2014 and reached over 76,000 in FY 2019.

The apprehension numbers for family units follows the same trend: Rising from nearly 15,000 in FY 2013 to over 473,500 in FY 2019. What kicked the family unit numbers into the stratosphere was the 2015 decision by a California district court that expanded the Flores detention settlement, requiring accompanied minors (as well as unaccompanied minors) to be released from immigration detention within 20 days.

What turned the tide of illegal entry was implementation of the Migrant Protection Protocols in January 2019. These protocols ended the “catch and release” policy and replaced it with a policy of returning illegal entrants to Mexico until immigration courts ruled on their requests for asylum.

Mexico and Central America’s cooperation, in turn, began requiring “caravaners” to return to the first safe country they entered after leaving their native lands.

These enforcement consequences have significantly cut illegal immigration. The apprehension numbers have consistently decreased.

To keep this trend going, however, will require a statutory change to the Flores settlement, a permanent end to DACA, and applying immigration consequences to illegal immigrants here, regardless of their age upon arrival. The mere prospect of green cards for “young” illegal immigrants will unravel the operational control Customs and Border Protection has struggled to achieve. Apprehension numbers would again balloon.

Lawmakers have tried to pass an amnesty package nearly every Congress since the first DREAM bill in 2001. But this Congress and the Trump administration have experienced something new: They have witnessed a true crisis on our southwest border and how hard it has been to gain operational control of it. And they have clear evidence of how the misguided policies of the Obama era exacerbated the problems.

If our political leaders decide to offer green cards to those here illegally instead of applying the legal consequence of deportation, they cannot claim ignorance of what will follow. By embracing amnesty, they will knowingly draw even more illegal immigrants, worsening the border crisis all over again.