In most parliamentary democracies, the party in power calls (or holds) an election every five years. However, if the parliament does not care for or have trust in the Prime Minister, he or she can be removed from office and another election for the position can be held.
The anti-federalist felt that the constitution would give too much power to the federal government. They basically were opposed because of what was in it or what wasn't in it because of fear that their civil liberties would be stripped off due to everyone functioning off of the constitution. They more so wanted a bill of rights to proclaim all the liberties a citizen is granted to avoid this.
He was the king from 1760 until his death in 1820