'Alarums and excursions' is an Elizabethan stage direction; Shakespeare and others used it. 'Alarum' is an old form of 'alarm', which derives from the Italian phrase "all'arme!" meaning "To arms!" 'Excursion' is here used in an old sense 'sally, sortie, raid'. The whole phrase used as a stage direction meant that all the extras dressed as soldiers were to dash about the stage shouting "To arms!" and generally giving the impression of exciting military action. -- The Phrase Finder.
The National Review reports "White House Does Damage Control on NYT Gun-Control Report," which refers to this article: "Tough Path Seen by Obama on Ban of Assault Weapons."
There are many rumors floating around about what's coming from the administration and its Nazgul, within and without Mordor on the Potomac. Executive orders of bans on importation of "assault weapons," parts and ammunition are rumored. So, too, says one unconfirmed source, is a temporary suspension of NICS checks, thus freezing the system. The administration, it is said, is panicked by the rush to buy arms and ammunition. (See Chuck the Schmuck's letter to the CEOs of Wal-Mart, Cabela’s, Bass Pro Shops, Gander Mountain, Sports Authority, Academy Sports and Outdoors and Big Five Sports.)
While I have no doubt that the Schumers of the world are panicked, it behooves us to await more details and further events before WE panic into "alarums and excursions." This doesn't mean that we should quit making preparations, on the contrary. It doesn't mean that we shouldn't engage in political struggle against the tide. But the wise man waits and watches without panic until action is required.