Short answers, pulled from the story.
George Washington took office in 1789 as the first president of the United States. His decision to retire after two terms established a precedent that shaped the nation for over a century.
The Presentment Clause gives the president the power to sign or veto any bill passed by Congress while Article II vests executive power to command the armed forces. The War Powers Resolution enacted over Nixon's veto in 1973 requires authorization for troop deployments longer than sixty days yet relies on triggering mechanisms never employed by either branch.
In Trump v United States decided the 1st of July 2024 the Supreme Court granted absolute immunity for core constitutional powers while presuming immunity for other official acts. No former or current president had ever been criminally indicted until this ruling addressed Donald Trump's alleged election subversion in January 2024.
Twenty-seven electoral votes are required out of 538 possible to win the presidency under Article II Section 1 Clause 2. Each state receives electors equal to its total congressional delegation size with Maine and Nebraska awarding two statewide electors plus one per congressional district unlike other states which use winner-take-all systems.
John Tyler declared himself fully president upon William Henry Harrison death in 1841 refusing papers addressed to Acting President. Congress accepted this interpretation despite ambiguity in Article II Section 1 Clause 6 regarding succession powers.