Senate Majority Leader Harry Reid has the tools he needs to overcome any initial filibuster of a firearms background check bill, but he may not be inclined to use them. Indeed, the Nevada Democrat is biding his time, even as President Barack Obama embarks on an aggressive new push for votes on a variety of gun-related measures, including background checks and a new prohibition on assault weapons. The trouble for Reid is the new process — established in January through modest filibuster rules changes — may have a fatal flaw in practice when the Nevada Democrat actually wants the bill...