CBS News reported last night that investigators believe that the unemployed Tamerlan Tsarnaev may have financed his terrorist plot through the sale of marijuana — an interesting occupation for a fanatical Muslim. The composition of the bomb has come into clearer focus as well. The triggering device came from a remote-control car, and the fed still think the gunpowder may have come from fireworks. Most interesting, though, is the acknowledgment that the Tsarnaevs only had one firearm on them during their gunfight with police: The search through landfills should remind us that bombers need quite a bit of practice in...