Many people are confused by the fact that only States can vote for President. The most a person's vote can do is provide input into their State's votes for President.
It has never happened, but if there once would be enough faithless electors to swing the election (choosing a different president than what people voted for) it would be a huge scandal and it would be widely condemned as undemocratic.
There has been so far 5 elections where the electoral vote chose a different president than what the popular vote count would have chosen. But this is a different thing than what I was talking about.
https://en.wikipedia.org/wiki/List_of_United_States_presiden...
The UK pm and the POTUS are both ultimately accountable through elections. In the UK, a general election can change the government. In the US, people vote specifically for presidential electors, even if it’s through the Electoral College.
The EU commission is different. People don’t vote for commissioners or the president, and they can’t vote them out in the same direct way.
the US president is appointed by politicians who are elected, and the only accountability mechanism for president is impeachment, which is again, indirect via elected politicians.