WASHINGTON -- Comprehensive immigration reform is in jeopardy because it is a complex compromise with too many moving parts and too many competing interests. Employers want a guest worker program; unions want to kill it. Reformers want to introduce a point system that preferentially admits skilled and educated immigrants; immigrant groups naturally want to keep the existing family preference system. Liberals want legalization now; conservatives insist on enforcement "triggers" first.

There is only one provision that has unanimous support: stronger border enforcement. I've seen senators stand up and object to the point system, to chain migration, to guest workers, to every and any idea in this bill -- except one. I have yet to hear a senator stand up and say she is against better border enforcement.

Why not start by passing what everyone says they want? After all, proponents of this comprehensive reform insist that the current situation is intolerable and must be resolved. It follows, therefore, that however much they differ in the details of how the current mess should be resolved, they are united in the belief that such a mess should not be allowed to happen again. And the only way to make sure of that is border control.

So why not pass it, with the understanding that the other contentious provisions would be taken up subsequently? Because for all the protestations, many of those who say they are deeply devoted to enforcement are being deeply disingenuous. They profess to care about immigration control because they have to. But they care so little about the issue that they are willing to make it hostage to the other controversial provisions, most notably legalization.

Why am I so suspicious about the fealty of the reformers to real border control? In part because of the ridiculous debate over the building of a fence. Despite the success of the border barrier in the San Diego area, it appears to be very important that this success not be repeated. The current Senate bill provides for the fencing of no more than one-fifth of the border and the placing of vehicle barriers in no more than one-ninth.

Instead, we are promised all kinds of fancy, high-tech substitutes -- sensors, cameras, unmanned aerial vehicles -- and lots more armed chaps on the ground to go chasing those who get through.

Why? A barrier is a very simple thing to do. The technology is well tested. The Chinese had success with it, as did Hadrian. In our time, the barrier Israel has built has been so effective in keeping out intruders that suicide attacks are down over 90 percent.

Fences work. That's why people have them around their houses -- not because homeowners are unwelcoming, but because they insist that those who wish to come into their domain knock at the front door.

Fences are simple. They don't require much upkeep. Two fences with a patrol road between them across the length of the U.S.-Mexico border would be relatively cheap, easy to build and simple to maintain. Continued...