1. Political parties

Rishi Sunak, the current UK PM, is a Conservative and Jo Biden, the current US president, is a Democrat.

2. Major elections

The UK general election

• Holding the election

• Holding a general election means electing the House of Commons, members of Parliament (MPs). Since 2011, general elections are held every 5 year. So the PM’s term lasts 5 years.
• The exception is an early or snap election which is what happened in 2017 and 2019, respectively called by Theresa May and Boris Johnson after Parliament agreed to it. The next GE is due in 2024.

• Winning the election

• In 2017 the Conservative Party won the GE with a simple plurality. Consequently Theresa May stayed PM (she resigned in July 2019, so not after the 2017 GE) as only a simple plurality is needed to be the winner.
• In May 2019, the Tory Party won the GE again, this time with a simple majority, and Boris Johnson remained as PM.

• Becoming PM

UK's PMs

• The first way to become PM in the UK is to be the leader of the party which won the GE. The other way is when the current PM resigns. As they also resign as party leader, the party organises a leadership contest and the newly elected party leader automatically becomes the new PM without calling a GE.
• However, they only officially become PM when the monarch appoints them - a conventional but necessary formality as constitutionally the head of government is appointed by the head of state.

=> In the UK, the party matters more than personalities. As long as it wins general elections, it stays in power. If party MPs are unhappy with their PM and leader, they can cause their resignation and elect a new party leader who then will be the new PM. It’s a parliamentary system.