Final answer:
George W. Bush's claim of presidential power was based on the use of signing statements and the unitary executive theory, which allowed him to interpret and potentially override legislation based on his duties as commander in chief and protector of the nation, particularly after the 9/11 attacks.
Step-by-step explanation:
One of former President George W. Bush's quotes regarding his claim of presidential power was tied to his use of signing statements as a means to assert the president's interpretation of legislation. Under his administration, he issued numerous signing statements, which were often justified on the grounds of inherent powers of the commander in chief and the unitary executive theory. This theory posits that the executive branch has the authority to overrule Congress and the courts if the president deems their actions as unconstitutional restrictions on executive power.
Moreover, after the 9/11 attacks, the War Powers granted him the unilateral ability to act to protect the American people, and his Office of Legal Counsel argued that these powers extended to doing whatever was necessary for that protection. This approach was encapsulated in the Bush Doctrine, asserting the right to engage in preemptive wars or change regimes to protect the United States from terrorist threats. Such actions and statements broadly expanded the use of presidential power.