ALPA has the infrastructure in place to conduct a nation-wide Suspension of Service. It's been termed "ALPA's Nuke." Just like any nuke, there is alot of collateral damage. Even though ALPA is for armed pilots as is the general public, the issue isn't quite as pivotal in the live's of the line pilot as one might think. The SOS is reserved for fundamental, precedent setting issues, such as pivotal safety issues (terrorism being important, of course, but not all that likely), the wholesale abrogation of labor contracts, the criminalization of routine errors, major threats to Captain's Authority, and the like. A nationwide strike would of course be illegal, as all airline workers are governed by the Railway Labor Act which places elaborate legal roadblocks in front of a wildcat strike.