Terry Jeffrey writes at CNSNews.com:

The federal government has a duty to enforce this nation's borders and do it in a humane manner that minimizes harm to human life both inside U.S. territory and on the approaches to it.

The best way to do that at the border with Mexico is to build effectively impermeable barriers that send a simple, straightforward message: You can only cross this border legally.

Not securing the border does harm. "By failing to secure the border, the federal government not only allows foreign nationals to come here illegally to live and work, but also provides an avenue for deadly drugs, for the criminals who bring them and for potential terrorists." Jeffrey writes.

"Failure to secure our border not only harms people in the United States, it also harms people in Mexico and would-be illegal border crossers. Mexicans are victimized by the drug cartels that exploit our unenforced border, and migrants seeking to cross our unsecured border to illegally live or work here put themselves at risk in remote regions and in the custody of human traffickers," Jeffrey explains.

Americans "should not turn" their backs "on those who seek refuge and asylum, especially Middle Eastern Christians who face genocide by Islamic State terrorists," Jeffrey writes. "Nor do we need to stop legal immigration."

However, Jeffrey concludes, the legal obligation to secure the "border of the United States is a just law that the federal government has [a] duty to enforce. Building walls that deter and stop illegal crossers is a humane way to do it."