When most Texans think of border security, they think of it as a one-way street — unauthorized immigrants crossing the Rio Grande from Mexico into Texas.

Mexicans — especially those engaged in a bloody battle with drug cartels — consider it a two-way avenue. While a porous border allows the United States to receive a stream of unskilled laborers for low-paying jobs, it also permits a flood of weapons and ammunition to flow into Mexico, arming the drug lords for their reign of terror.

In the first of a three-part series, “Texas' Deadliest Export,” Express-News reporter Todd Bensman has begun to put the cross-border gun trade into focus. According to the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, Texas gun sellers were the source of 1,131 weapons found discarded last year at shootings in Mexico or confiscated from the drug cartels.

That's the most of any state, and more than twice the number of guns traced to second-place California. This year alone, criminals in Mexico have used illegal arms to kill more than 4,000 people. The escalation of violence in Mexico often spills across to this side of the border…

Mexican political and law enforcement leaders are risking, and in many cases, losing their lives in the war with drug traffickers. Americans can help them, help border security and help themselves by doing two things.

First, put more ATF agents on the border, both in the United States and Mexico. Thanks to legislation pushed by Rep. Ciro Rodriguez, D-San Antonio, and Sen. Kay Bailey Hutchison, R-Texas, funding is now in the pipeline to add more agents to investigate and prosecute weapons smugglers.

Second, close the U.S. gun show loophole that allows a huge amount of gun sales to take place without background checks or documentation. Licensed gun stores are required to run the checks and maintain paperwork on gun sales. Sales at gun shows, however, are exempted. Closing the loophole would level the playing field and hold all gun sellers to the same standard.

Too often, the discussion of border issues devolves into a deliberation about Mexico's failures. The United States has its failures, too. Whether the issue is immigration or drug-fueled violence, the United States and Mexico must work together to improve border security.