OPINION:
For much of his presidency, Joseph R. Biden insisted and was ridiculed for claiming that he “need[e]d Congress to act” to secure the border. President Trump has proved that wasn’t true; we just needed a commander in chief willing to use the powers Congress gave the Department of Homeland Security.
As violent opposition to immigration enforcement surges, Mr. Trump should assess the authorities Congress has given him to deport the millions of unauthorized aliens in the interior. Then he should use them.
We often think of immigration enforcement in terms of U.S. Immigration and Customs Enforcement officers going to state or local jails to take criminal aliens into custody, or arresting aliens on the streets and in communities. Such arrests are crucial to any enforcement scheme, regardless of the agency, but they aren’t the only way Congress envisioned the immigration laws being enforced.
When Congress offered amnesty to 3 million illegal aliens in 1986, it also made it a crime for employers to knowingly hire aliens who were either here illegally or lacked work authorization. To enforce that mandate, Congress required employers to review the identification documents of new hires to ensure they could work here legally. It also gave immigration officers sweeping new powers to review businesses’ paperwork to ensure they weren’t skirting the law.
If officers have questions about the work authorization of any of those employees, they can seek the business’ consent to “speak to” the employees in question or get a warrant to enter the workplace and start questioning the workers.
A single street arrest can involve a team of officers and generally nets, at most, one or two removable immigrants.
If the same ICE team “audits” a single workplace, on the other hand, it can result in hundreds of arrests and send a message to entire industries and communities that there are no more “shadows” where it’s safe to ignore the law.
To be fair, such “briefcase enforcement,” as my colleague Mark Krikorian calls it, isn’t as exciting as hitting the streets to find criminals, but it offers fewer targets for the “constitutional observer” crowd.
Then there’s a mandate Congress implemented in 1940 requiring aliens 14 and older to register their presence here within 30 days of arrival.
That applies to all aliens, not simply those who come legally. It also requires those aliens to carry proof of registration at all times — the reason most lawful immigrants carry their “green cards” in their wallets.
Aliens’ willful failures to register, update their addresses or carry registration receipts are all unique federal criminal offenses. (Remember this when somebody claims it’s not a “crime” to be here unlawfully.)
It’s time for the Homeland Security Department to start calling in illegal aliens who have registered and prosecute those who either won’t respond or haven’t registered. Deportation is one thing; federal prison time is something else entirely.
Finally, a deportable alien under a final removal order who willfully refuses or fails to leave within 90 days has committed yet another federal crime, this one carrying a fine and up to four years in prison. Just a handful of prosecutions would send a message to hundreds of thousands of others.
Public immigration arrests can result in confrontations, but they aren’t the only enforcement tool the Homeland Security Department has. Mr. Biden didn’t need congressional action to enforce the immigration laws, and President Trump doesn’t either.
• Andrew Arthur is a fellow in law and policy at the Center for Immigration Studies.

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