Some in Congress are sure that a proposed 700 mile fence along the Mexican border is the solution to the nation's problems with illegal immigration. But while it may deter some, to others with a bolt cutter or a shovel, it only represents a few minutes of extra effort.
And since the days of "The Berlin Wall", security fences have taken on huge political meanings. President Fox of Mexico has voiced strong opposition to the security fence idea. And even the Bush Administration cut more than $280 million dollars in loan guarantees to Israel after they constructed a security wall. There is always a political cost to pay when a nation erects a security device along it's borders.
And security fences are never completely effective. A security fence in India has only slowed illegal immigration from Bangladesh from 65,000 to 10,000 a year. Security fences are easy victims of bolt cutters or shovels. Walls are more effective, but mask efforts to dig under the device and slip under and into the night on the other side.
Many from South America present no worse security threat than work as labor in the U.S. It is through Canada or by legal air travel that many who are security threats to the U.S. may be in America. As many as 17,000 persons from nations in which Al Qaeda are active are in the U.S. that is currently estimated.
But a more serious internal threat than Al Qaeda efforts within the U.S., are organized Iranian efforts. At least two Iranian embassy persons were removed for conducting surveillance for a suspected proIranian terrorist network that operates within the U.S. This could be Iran's secret weapon within the U.S., to hit soft civilian targets and monuments if tensions with Iran come to heads over their nuclear program.
In WWII, some German sailors entered the New Jersey coast on a raft from a U Boat to perform terrorist bombings of American civilians. They were captured, and all but one were executed for spy activity and terrorism by the U.S. goverment. State sponsored terrorism from Iran could well be a bigger threat than Al Qaeda.
Al Qaeda has not attacked in the U.S. for several reasons. After 9/11 there has been better security. Al Qaeda lacks the infrastructure and a large enough device to attack in the U.S. comparable to 9/11 in scope. But perhaps most importantly, their is little political objective to achieve in a U.S. attack at this time.
Attacks in London, Jordan , Iraq or other areas where Al Qaeda is active are largely against soft and poorly protected civilian targets meant to achieve a political objective such as separating support from the U.S. or to weaken the U.S. mission in Iraq. It would serve little political purpose at this time to further enrage Americans with an attack that could fuel stronger U.S. actions in more Islamic states. It is now the objective to attempt to remove American influence from those states, not to increase it.
There are legitimate security issues for the U.S. However the image of a security fence or wall running along 700 miles or more of the American border is a powerfully bad political symbol to many in the world. Some might even say, "Mr. Bush, tear down this wall".