Showing rare bipartisan determination, Republicans and Democrats after the November election vowed to fix the nation's obsolete immigration system, aiming to have a bill drafted by March.

The so-called Gang of Eight in the U.S. Senate crafting that bill has hit a big stumbling block – the same obstacle that has stopped previous efforts at reform – and senators have left for a two-week recess.

Only if the Southwestern border is deemed "truly secure" will some of them move forward on broader immigration measures. Of course, the border never can be perfectly sealed, so we never get to next steps.

Congress continues to embrace a policy that has morphed over the last two decades from "enforcement first" to "enforcement only" – leaving us with a rigid system of caps and quotas dating back to the 1950s that hampers legal immigration and feeds illegal immigration.

Ironically, the border is more secure than ever and we now have net-zero migration from Mexico. And, no, this is not just because of the downturn in the U.S. economy or fear of drug cartel violence on the Mexico side of the border.

Researchers, including J. Edward Taylor at UC Davis, conclude that those recent factors are secondary. We are seeing a permanent shift in the migration dynamic.

Women in Mexico are having fewer children – with birth rates dropping from 6.8 children per woman in 1970 to just above 2 today. That means fewer young workers entering the workforce. They are better educated. On top of that, Mexico's economy is stronger, providing opportunities for higher wage work than in the past.

This long-term structural change adds up, writes Taylor and his colleagues, to a "permanent supply shift" in migration to the United States. The "fields of gray" that Bee reporter Peter Hecht described in his March 10 story, "Farms feel the pinch as younger workers reject harvest's toil," are here to stay.

The Gang of Eight is simply out of touch with reality to insist that we must have more Border Patrol agents, fences and drones to prevent "every unauthorized entrant" before launching any "road to a green card," the first step on path to citizenship.

Worse, some of the gang is insisting that a four-state commission of governors, attorneys general and community leaders in the border states of California, Arizona, New Mexico and Texas should determine when the border is "truly secure." Yet under the U.S. Constitution, immigration policy is the exclusive province of the federal government and must be decided by Congress and the president for the nation as a whole. Congress should not allow a local veto over national immigration policy.

Twenty years ago, we had 3,500 Border Patrol agents at the Southwestern border. Today, we have more than 18,500. We have 651 miles of fencing.

Our increasingly fortified border also has drone surveillance, which should give Americans pause. Because of the "border exception" to the U.S. Constitution's prohibition against "unreasonable searches and seizures," Sen. Tom Coburn, R-Okla., concludes that drones potentially tracking cellphones 100 miles inside the U.S. border would "fly in the face of civil liberties." Indeed, Coburn continues, "We must ask whether the trade-off in terms of border security is worth the privacy sacrifice."

Border security should concentrate, writes former Arizona Attorney General Terry Goddard, on dangerous criminal cartels smuggling drugs into the United States, and money and guns out. He believes that to get to the next step of reducing illegal flows of people seeking work or reuniting with their U.S. citizen relatives, we need to provide adequate legal channels of immigration. He is right.

The Gang of Eight and other members of Congress should stop using the border as an excuse and move forward with pursuing broader immigration reform.

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by the Editorial Board

Order Reprint