President Bush has quietly claimed the authority to disobey more than 750 laws enacted since he took office, asserting that he has the power to set aside any statute passed by Congress when it conflicts with his interpretation of the Constitution.

Among the laws Bush said he can ignore are military rules and regulations, affirmative-action provisions, requirements that Congress be told about immigration services problems, "whistle-blower" protections for nuclear regulatory officials, and safeguards against political interference in federally funded research.

Legal scholars say the scope and aggression of Bush's assertions that he can bypass laws represent a concerted effort to expand his power at the expense of Congress, upsetting the balance between the branches of government. The Constitution is clear in assigning to Congress the power to write the laws and to the president a duty "to take care that the laws be faithfully executed." Bush, however, has repeatedly declared that he does not need to "execute" a law he believes is unconstitutional.

The chairman of the Senate Judiciary Committee, accusing the White House of a "very blatant encroachment" on congressional authority, said yesterday he will hold an oversight hearing into President Bush's assertion that he has the power to bypass more than 750 laws enacted over the past five years.

"There is some need for some oversight by Congress to assert its authority here," Arlen Specter, Republican of Pennsylvania, said in an interview. "What's the point of having a statute if . . . the president can cherry-pick what he likes and what he doesn't like?"