It has been well established under the Constitution and throughout our history that the president’s job as the chief federal law enforcement officer permits him to put his ideological stamp on the nature of the work done by the executive branch. The courts have characterized this stamp as “discretion.”
Thus when exercising their discretion, some presidents veer toward authority, others toward freedom. John Adams prosecuted a congressman whose criticism brought him into disrepute, an act protected by the First Amendment yet punishable under the Alien and Sedition Acts, and Thomas Jefferson declined to enforce the Acts because they punished speech, and pardoned all those convicted. Jimmy Carter asserted vast federal regulatory authority over the trucking and airline industries, and Ronald Reagan undid nearly all of it.
The president has discretion to adapt law enforcement to the needs of the times and to his reading of the wishes of the American people. Yet that discretion has a serious and mandatory guiding light — namely, that the president will do so faithfully.
The word “faithfully” appears in the oath of office that is administered to every president. The reason for its use is to assure Americans that their wishes for government behavior, as manifested in written law, would be carried out even if the president personally disagrees with the laws he swore to enforce.
This has not always worked as planned. President George W. Bush once famously signed into law a statute prohibiting federal agents without a search warrant from reading mail sent to persons other than themselves — and as he was literally holding his pen, he stated he had no intention of enforcing it. That was a rejection of his presidential duties and a violation of his oath.