How do you tell when Bush is lying?

From Reuters [1]: 

President Bush has decided not to renew a program of domestic spying on terrorism suspects, Attorney General Alberto Gonzales said on Wednesday, ending an law-enforcement tactic criticized for infringing on civil liberties. 

"The president has determined not to reauthorize the Terrorist Surveillance Program when the current authorization expires," Gonzales wrote in a letter to congressional leaders. 

But wait, not only did the administration repeatedly say this was legal [2], but they also said as recently as the last few months that it was working [3].  Why would the administration want to abandon a tactic that is supposedly successful in curbing terrorism?