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.

[...]

Bush is the first president in modern history who has never vetoed a bill, giving Congress no chance to override his judgments. Instead, he has signed every bill that reached his desk, often inviting the legislation's sponsors to signing ceremonies at which he lavishes praise upon their work.

Then, after the media and the lawmakers have left the White House, Bush quietly files ''signing statements" -- official documents in which a president lays out his legal interpretation of a bill for the federal bureaucracy to follow when implementing the new law. The statements are recorded in the federal register.

In his signing statements, Bush has repeatedly asserted that the Constitution gives him the right to ignore numerous sections of the bills -- sometimes including provisions that were the subject of negotiations with Congress in order to get lawmakers to pass the bill. He has appended such statements to more than one of every 10 bills he has signed.

"He agrees to a compromise with members of Congress, and all of them are there for a public bill-signing ceremony, but then he takes back those compromises -- and more often than not, without the Congress or the press or the public knowing what has happened," said Christopher Kelley, a Miami University of Ohio political science professor who studies executive power.

[...]

The Constitution grants Congress the power to create armies, to declare war, to make rules for captured enemies, and ''to make rules for the government and regulation of the land and naval forces." But, citing his role as commander in chief, Bush says he can ignore any act of Congress that seeks to regulate the military.

On at least four occasions while Bush has been president, Congress has passed laws forbidding US troops from engaging in combat in Colombia, where the US military is advising the government in its struggle against narcotics-funded Marxist rebels.

After signing each bill, Bush declared in his signing statement that he did not have to obey any of the Colombia restrictions because he is commander in chief.

Bush has also said he can bypass laws requiring him to tell Congress before diverting money from an authorized program in order to start a secret operation, such as the ''black sites" where suspected terrorists are secretly imprisoned.

Congress has also twice passed laws forbidding the military from using intelligence that was not "lawfully collected," including any information on Americans that was gathered in violation of the Fourth Amendment's protections against unreasonable searches.

Congress first passed this provision in August 2004, when Bush's warrantless domestic spying program was still a secret, and passed it again after the program's existence was disclosed in December 2005.

On both occasions, Bush declared in signing statements that only he, as commander in chief, could decide whether such intelligence can be used by the military.