US Homeland Security Secretary Markwayne Mullin told Congress on 26 June that the Trump administration intends to complete both the primary and secondary border wall along the US-Mexico border before President Donald Trump leaves office, while simultaneously expanding smart fencing, drone surveillance and sensor technology to counter the evolving tactics of Mexican drug cartels.

What Mullin Told Lawmakers

Appearing before the House Appropriations Subcommittee on Homeland Security, Mullin said the administration was adapting its border strategy as criminal organisations increasingly turned to tunnels, drones and other bypass methods. 'The more walls we put, the more we can focus on trafficked areas,' he said. 'We just discovered our first tunnel in years because our wall is being effective. We are pushing them into what we consider chokepoints.'

Mullin was unequivocal about the timeline. 'I'll have it done before President Trump is out of office,' he said. 'We'll have the complete primary and secondary wall done.' He added that the secondary barrier would give Border Patrol agents critical response time after cartels breached the first fence.

Smart Fencing and Drone Technology

Beyond physical barriers, Mullin outlined a layered security approach. 'We're putting in smart fences, which allows us to respond when they're tampering with the wall,' he said. The department is also deploying unmanned aerial systems (UAS) equipped with heat sensors to track movement in real time.

Mullin acknowledged that cartels were constantly adapting. 'There's not one inch of Mexico's northern border that isn't covered by a plaza,' he told the subcommittee, referring to cartel territorial control. The Department of Homeland Security (DHS) is studying vulnerable sections of the nearly 2,000-mile US-Mexico border while balancing security needs with concerns raised by border communities.

Bipartisan Debate on the Best Approach

The hearing drew bipartisan discussion, though lawmakers differed sharply on strategy. Congressman Henry Cuellar, the ranking Democrat on the subcommittee whose district spans part of the Texas-Mexico border, acknowledged a significant decline in illegal crossings but urged the administration to consult border communities before expanding wall construction.

'I believe in strong border security,' Cuellar said. 'But it's got to be more than physical barriers.' He argued that technology, intelligence sharing and trained personnel had driven the improvement. 'The numbers went down without a single foot of border wall being constructed,' Cuellar said. He invited Mullin to visit Laredo to discuss concerns about wall alignment and its impact on private property — an invitation Mullin accepted.

Broader Context and What Comes Next

Border security and immigration have remained central pillars of Trump's second-term agenda. The administration has sought billions of dollars from Congress to expand physical barriers, recruit additional enforcement personnel and deploy advanced surveillance technologies aimed at disrupting transnational criminal organisations.

This comes amid a broader push by the administration to frame border security as a multi-layered effort — combining artificial intelligence, drone fleets, sensor-equipped surveillance towers and a completed wall system. How quickly DHS can deliver on Mullin's commitment, and whether Congress will fund the full scope, remains to be seen.