The border fence on the US-Mexico border continues to face problems in its development.

From the New York Times:

As the Department of Homeland Security pushes to complete 670 miles of fencing along the Mexican border by the end of this year, it is confronting the sharpest resistance yet while conceding that physical barriers alone do not stop illegal crossings.

In the latest challenge, the Texas Border Coalition, an organization of mayors, county commissioners and economists opposed to the fence, filed a federal lawsuit on Friday. It says that the homeland security secretary, Michael Chertoff, failed to conduct required negotiations with property owners and local authorities when he ordered that the barrier be built in Texas. The group wants the construction halted.

The protests come as known efforts at illegal crossings — measured by the number of people detained at the border — have fallen 17 percent this year, after declining 20 percent in 2007, figures that Chief David V. Aguilar of the Border Patrol points to as proof that the overall approach to border enforcement is working.

Still, Mr. Aguilar and other officials acknowledge, the new fencing has mainly proved useful when it has been backed up with other enforcement methods, like electronic surveillance and aggressive prosecution of illegal immigrants caught by the Border Patrol.