Homeland Security Department Secretary John Kelly said in a recent Meet the Press interview that a wider array of criminal behavior by illegal immigrants, including DUIs, could lead to their deportation.

He added that during President Barack Obama’s administration a DUI was unlikely to result in deportation even though it would have put the alien in the DHS system.

The United States, Kelly stressed, has a legal justice process that allows it to deport aliens, and that practice is consistent with President Donald Trump’s new enforcement-first policy.

“The definition of criminal has not changed, but where on the spectrum of criminality we operate has changed,” he said.

But as clear as federal immigration laws are in their definition of who is deportable, Kelly’s frank statement that a DUI could expedite removal is certain to spark more protests that Trump’s commitment to enforcement is extreme.

The American Civil Liberties Union condemned Kelly, even before he was confirmed, for his reasonable warning that unchecked immigration represents a national security threat.

The law on what’s generally referred to as improper entry or entry without inspection is unambiguous: Whether by crossing the U.S. border alone, with a coyote’s help or buying a fake U.S. passport, a foreign national who enters the United States illegally and not through a designated port of entry can be both convicted of a crime and fined.

For the first improper entry, a civil violation, the alien can be fined or imprisoned for up to six months, or both. A subsequent offense, a felony, carries a fine or imprisonment for up to two years, or both.

Immigration laws also apply to visa overstays that make up as much as 40 percent of the 12 million illegal immigrants residing in the United States. When an alien crosses into the United States illegally or enters on a valid, legal visa but fails to depart on the designated date, Immigration and Nationality Act Section 237 applies: “Any alien who is present in the United States in violation of this Act or any other law of the United States … is deportable.”

Despite the law’s crystal clarity, Congress’ legislative branch, which includes many lawyers, can’t agree on who should remain. For some legislators, aliens who get past the Border Patrol or visitors on a temporary visa who overstay should be allowed to remain indefinitely.

But illegal entry will never end unless laws are enforced. When immigration laws are enforced, living illegally in the United States becomes more challenging and less satisfying.

Attrition through enforcement is better for taxpayers and for foreign nationals unlawfully present. Taxpayers don’t have to spend billions of dollars to subsidize DHS’ deportation efforts, and illegal immigrants can return home on their own terms when they realize that the option — forced removal — is less appealing.

There is precedent for returning home voluntarily. According to a Pew Research Center study, between 2009 and 2014, the years that immediately followed the recession and the dried-up job market, more than 1 million Mexicans returned home; only 14 percent were deported.

The Trump administration’s stepped-up enforcement helps American citizens and legal permanent residents get jobs, and discourages future illegal immigration, already down 40 percent from Mexico during January and February.

The sharp drop in illegal immigration should encourage Trump to continue his interior enforcement commitment. He campaigned on an enforcement platform, and now he’s delivering.

— Joe Guzzardi is a senior writing fellow for Californians for Population Stabilization (CAPS) who now lives in Pittsburgh. He can be reached at joeguzzardi@capsweb.org, or follow him on Twitter: @joeguzzardi19. Click here to read previous columns. The opinions expressed are his own.

Joe Guzzardi is an Institute for Sound Public Policy analyst who has written about immigration for more than 30 years. A California native who now lives in Pittsburgh, he can be reached at jguzzardi@ifspp.org. The opinions expressed are his own.