is the president the head of his political party
Party leader In the Gilded Age (late 19th century in the United States), the government was known as Bossism. This government entailed powerful political machines, run by so-called "bosses" who awarded political positions to their associates (one example being Tammany Hall which was run by Boss Tweed) This kind of political system is also referred to as a particracy. Party leaders in the United States mostly refer to the President, Vice President and leaders of the Congress in both parties.