Nick R. Martin of Talking Points Memo looks at how extremists are now experimenting with explosives on the border:

Arizona became a hotbed for a certain brand of extremist groups in the past decade as it took center stage in discussion about how to handle the nation’s broken immigration system. But while a report by the nation’s leading watchdog of the extremist movement shows the numbers of so-called “border watch” groups are dwindling, some that remain have shown a surprising penchant for violence. They are armed, angry and desperate to fight in what they see as a real-life war taking place in the nation’s borderlands.

In just the past few years alone, federal agents in Arizona have gone on a hunt for a man who claimed to have littered the desert with explosive devices. They have been told a Minuteman-style organization planned to shut down a major freeway. They have discovered a bomb planted along a known smuggling route. And more recently, a militia group has talked openly about buying a tank to combat what it calls “narco terrorism” flowing across the border.