Officials nabbed Daniel Rendón Wednesday. Colombia has used extradition and technology to make headway against drug lords.
Summit of the Americas gathers the 34 democratically governed countries of the Western Hemisphere. But communist Cuba threatens to steal some of the spotlight.
But they're still cautious as they hold out hope that this American president might be different.
He vows to support a regional treaty to curb gun trafficking as well as greater cooperation on clean energy.
He's likely to stress shared responsibility for rising border violence during trip that begins Thursday.
Ousted governor pleaded not guilty to federal charges on Tuesday, as political watchdogs tally cost of state's long history of graft and cronyism.
Most are, say US officials. But the NRA says the Obama administration is inflating the scope of the problem and threatens to undermine the Second Amendment.
In recent years, states have barred undocumented students from getting the lower tuition fees.