WASHINGTON (CNN) - The legality of presidential "signing statements" has to be decided on a case-by-case basis, Judge Sonia Sotomayor said Tuesday.
Sotomayor weighed in on the hotly contested subject during her Supreme Court confirmation hearings after Sen. Dianne Feinstein, D-California, criticized former President Bush's decision to sign a 2005 bill banning torture only after attaching several caveats.
Feinstein noted that Bush issued a signing statement specifying that he would only enforce the measure when "consistent with the constitutional authority of the president to supervise the unitary executive branch."
Bush also said that the measure must be "consistent with the constitutional limitations on the judicial power."
Asked if the Constitution authorizes the president "to not follow parts of laws duly passed by the Congress that he is willing to sign," Sotomayor would only say that "the factual scenario before the court" must be considered in each particular situation.
She cited a framework set Justice Robert Jackson during President Harry Truman's seizure of several steel factories during the Korean War in order to prevent a strike.
According to Jackson, Sotomayor said, "you always have to look at an assertion by the president that he or she is acting within executive power in the context of what Congress has done or not done."
First, "you look at whether Congress has expressly or implicitly addressed or authorized the president (to) act in a certain way. And if the president has, then he's acting at his highest stature of power."
If, on the other hand, "the president is acting in prohibition of an express or implied act of Congress, then he's working at his lowest ebb."
But if a president acts "where Congress hasn't spoken, then we're in what Justice Jackson called a 'zone of twilight.'"
In each instance, she argued, you have to start "with what Congress says or has not said, and then looking at what the Constitution ... says about the powers of the president minus Congress's powers in that area."
But at the end of the day, Sotomayor concluded, a "president can't act in violation of the Constitution. No one's above the law."
In the 2008 case Doe v. Mukasey, Sotomayor joined a unanimous 2nd Circuit panel that found several Patriot Act provisions improperly stripped the federal courts of the power to review the government's decisions.
The law would improperly "cast Article III [federal] judges in the role of petty functionaries, persons required to enter as a court judgment an executive officer's decision, but stripped of capacity to evaluate independently whether the executive's decision is correct," the panel concluded.
"Under no circumstances should the Judiciary become the handmaiden of the Executive Branch. ... The Constitution envisions a role for all three branches when individual liberties are at stake."
–CNN's Bill Mears contributed to this report