The Bush Gang keeps citing the authorization to use force as giving themselves everything short of the powers of Superman. But take a plain look at one word.
That word: "Appropriate."
The resolution adopted by Congress in 2001 authorized the president "to use all necessary and
appropriate force against those nations, organizations or persons he determines planned, authorized, committed or aided the terrorist attacks that occurred on Sept. 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States."
The resolution didn't authorize "all force." It authorized "necessary and appropriate" force.
Even if you extend the word "force" to include eavesdropping, most people -- specifically Senators, congressmen and judges -- would conclude that eavesdropping without a warrant is plainly illegal -- hence, inappropriate.