Watchdog: No way to measure US-Mexico border wall success

FILE - In this Nov. 16, 2015, aerial file photo, a U.S. border patrol vehicle appears near the border wall near Abram, Texas, from a U.S. Customs and Border Protection helicopter. Nearly 5,000 unaccompanied immigrant children were caught illegally crossing the U.S. border with Mexico in October, almost double the number from October 2014, according to U.S. Customs and Border Protection data. Also, in the figures released Tuesday, the number of family members crossing together nearly tripled from October 2014 — from 2,162 to 6,029. (Delcia Lopez/The Monitor via AP)

SAN DIEGO (AP) – A report by Congress’ watchdog says the United States still does not have a way to measure how well fencing works to deter illegal crossings from Mexico.

President Donald Trump is moving ahead with plans to erect a wall along the border. But the Government Accountability Office says in a report issued Thursday that ways to evaluate the effectiveness of border barriers should be developed first. Congressional leaders say the wall could cost up to $15 billion.

Fencing currently covers about 650 miles of the 2,000-mile border, much of it built during President George W. Bush’s second term. The report says fence construction cost $2.3 billion from 2007 to 2015.

The report estimates that fencing costs an average of $6.5 million a mile to build.