In most Western countries there is an extremely broadly held belief in individual liberty, which can be summed up as "do whatever you want as long as you don't unreasonably burden others". There is significant disagreement on what exactly does or does not "unreasonably burden others", but the core belief is held across the political spectrum for all except the extreme ends of the tankie left and fascist-y right.

Other differences, such as a belief in democracy, free speech, freedom of religion, etc. flow from this.