WASHINGTON — Militia groups with gripes against the government are regrouping across the country and could grow rapidly, according to an organization that tracks such trends. The stress of a poor economy and a liberal administration led by a black president are among the causes for the recent rise, the report from the Southern Poverty Law Center says. Conspiracy theories about a secret Mexican plan to reclaim the Southwest are also growing amid the public debate about illegal immigration. Bart McEntire, a special agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives, told SPLC researchers that this is the most growth he’s seen in more than a decade. ‘All it’s lacking is a spark,’ McEntire said in the report. It’s reminiscent of what was seen in the 1990s-right-wing militias, people ideologically against paying taxes and so-called ‘sovereign citizens’ are popping up in large numbers, according to the report to be released Wednesday. The SPLC is a nonprofit civil rights group that, among other activities, investigates hate groups. Last October, someone from the Ohio Militia posted a recruiting video on YouTube, billed as a ‘wake-up call’ for America. It’s been viewed more than 60,000 times. […]