Republicans interpreted their overwhelming victories as a mandate to change the course of the states. Specifically, they set about undoing decades of laws put in place by Democrats to favor labor unions over taxpayers.The notion of checks and balances necessarily implies tensions, as do the competing principles of majority rules and minority safeguards. Rules of order that specify a quorum, and rules of procedure that provide for filibuster, are ways to contain those tensions.
Spats over quorum calls and filibusters are nothing new. It's also nothing new to observe holders of a temporary majority seeking to overturn the existing protections. If you're Harry Reid tonight, you ought to be thinking very carefully about whether to give yourself powers that might be in the hands of Scott Walker's fellow-followers next year.