During World War II, when the Allies planned the invasion of Nazi occupied Europe, Winston Churchill actually proposed coming from the south, from the Mediterranean Sea and into the Balkans. That region was, as he called it, the “soft underbelly” of Europe, less guarded and ripe for a swift, piercing and fatal blow to Hitler’s regime.

For various reasons, the Allies chose the northern route through France, but Churchill’s premise that nations have geographic underbellies — soft, vulnerable and susceptible to would-be invaders — is absolutely true for us today. America’s southern border is our soft underbelly. Here an invasion by illegal aliens already is in progress, and one by terrorists could be soon, unless we act.

That’s why I support a bill now being considered by the Senate to build more extensive fencing on the Mexican border and employ an array of high technology surveillance and interception measures along it, including use of unmanned aerial aircraft like the type built here in Mississippi.

There has been much discussion of proposals to build a fence along our Mexican border. In this context, the word “fence” is a broad term which, along some parts of the border, will mean traditional vertical steel barriers, vehicle obstacles and additional checkpoints. Along more mountainous parts of our border, that “fence” will be composed of more people and better technology, including ground-based sensors, satellites, radar, cameras, and unmanned aircraft such as those now being built at Northrop Grumman’s new Moss Point factory. Together, this combination of high and low-tech fencing will help curb the unacceptable flow of illegal immigrants across our border and be geared toward helping weed out terrorists.

The fence is not a Berlin Wall, designed to close our border. Those desiring to come here legally may still go through the proper, legal channels to do so. It is designed to keep bad people out of this country, people who want to harm us.

Nor is a fence unprecedented along our border. In fact, we’re just expanding an existing fence. Currently there are 75 miles of fence and about 55 miles of vehicle barriers, with the most well-known fence running between San Diego and Tijuana.

The fence bill, officially called the “Secure Fence Act of 2006,” adds about 700 miles of double-layered fencing at specified locations along 2,000 miles of our southern border, primarily in flat or less mountainous areas where there is no natural barrier. Along the natural barriers like the Rio Grande River and in more difficult terrain, more people and better technology will be employed to intercept illegal aliens undeterred by the natural hazards or obstacles.

Within 18 months of the bill’s enactment, the Homeland Security Secretary must achieve “operational control” of our border. The target is stopping all illegal entries of people, weapons, and contraband. That’s certainly an ambitious goal, given the number of illegal aliens entering America from Mexico, but we must achieve it. Our national security depends on it, and to that end, Congress will require the Homeland Security Secretary to report regularly as we strive to attain full control of our border.

Among the American people and within Congress there is broad, bipartisan support for expanding our border fence. I hope that President Bush and my colleagues in Congress will support the fence. Without a doubt, terrorists are studying ways to pierce America’s soft underbelly and enact their next deadly blow. We must harden that border, using every means at our disposal, as soon as possible.

(Senator Lott welcomes any questions or comments about this column. Write to: U.S. Senator Trent Lott, 487 Russell Senate Office Building, Washington, D.C. 20510 (Attn: Press Office))