John Cleese did a political advert in 1987 for the SDP/Liberal Alliance, a moderate coalition of small UK parties that, as one would expect, got annihilated in the election that year, and ultimately became the Liberal Democratic Party. The LDP went on to get the shit kicked out of them in every election until the Tories found them useful for a hot second in 2010, whereupon they got kicked to the curb as soon as the Tories had an outright majority, before everyone forgot about them in 2015.
Anyway, his rant about extremism still has a lot of resonance today: