When the armies of Emperor Hadrian had troubles with fierce Scottish tribes in the first century A.D., Hadrian elected to build a wall between Roman Britain and Scotland. In the empire’s most western outpost, the Roman governors of Britain felt better separating “the Romans from the barbarians.”

Now Hadrian’s Wall – a stone-and-earth belt across the skinny waist of Great Britain – is a crumbled 73-mile reminder of how empires shouldn’t choose popular, but facile, solutions when faced with intractable border relations.

Maybe the 700 miles of new fencing between the U.S. and Mexico, as authorized by President George W. Bush, should come to be called “Bush’s Wall.”

The “Secure Fence Act of 2006” approves a plan to fence about one-third of the U.S. border with Mexico in response to immigration and security concerns. It has landed with a thud.

Protectionist groups, for example, call the bill “toothless” for approving, but not appropriating, the billions needed for the fence, checkpoints, and technology like cameras, satellites and drone aircraft to monitor the border. Implementing the Secure Fence Act is estimated to cost between $2 billion and $9 billion.

Opponents say the plan simply avoids what is really needed: comprehensive reform that addresses the roots of illegal immigration. Instead, they say, the plan is a spiteful solution to separate “good” from “bad.”

The U.S. cannot rely on failed ideas from the past to masquerade as practical immigration, economic or foreign policy. Mexican President Vincente Fox has called the fence an “embarrassment,” a sentiment shared by many. Bad fences – and this should be patently obvious – make bad neighbors.

And when dialogue should revolve on the fence’s impact on immigration policy and U.S.-Mexico relations, it has been absorbed by the political monster that is the war on terror.

“When it comes to critical national security legislation, Democrats have no agenda and offer no solutions,” House Speaker Dennis Hastert and Senate Majority Leader Bill Frist said in a joint statement about the law. “House and Senate Republicans will continue to provide the president with the tools necessary to win the Global War on Terror and will stop the hemorrhaging along our nation’s borders.”

With all due respect to the speaker and senator, the U.S. has more pressing hemorrhages – of both money and blood – elsewhere that need stanching.

Fencing the windswept southwestern desert of Texas makes little sense. It sounds like progress, but in reality, it only assures the empire is separated from the “barbarians,” while ignoring the roots of why the border needs reinforcing at all.

Just like Hadrian’s Wall.

What the Roman Empire couldn’t conquer, it built a wall to exclude. What the U.S. couldn’t resolve, it may build a fence to control.

Now tourists stride along the mossy stones and abandoned forts of Hadrian’s Wall, a symbol of an overstretched empire’s failing foreign policy.

And what Bush’s Wall is destined to become.