To add: Beyond the need for compromise, a multi-party democracy also provides a safety valve; if a fringe element of a major party grows _too_ fringe, it will often just break off (in the last 20 years Ireland has had _two_ new minor parties emerge from an anti-abortion/anti-LGBT fringe breaking with a major party, say). In two party systems, you instead tend to get ‘big tent’ parties, with the fringe elements on the inside, and sometimes one of the fringe element takes over. For instance, see the US Republicans with Trumpism, the UK Conservatives with Brexiteers (and later an attempted, though largely failed, takeover by Truss’s lot, and, er, whatever the hell they’re doing now, who even knows anymore), and arguably UK Labour with Corbyn’s faction (again, this didn’t really last).
(The UK’s a bit of an oddity here in that it’s _kind_ of a multiparty state for historical reasons, but doesn’t really have the right type of electoral system to support a multiparty system.)
(The UK’s a bit of an oddity here in that it’s _kind_ of a multiparty state for historical reasons, but doesn’t really have the right type of electoral system to support a multiparty system.)