Counterexamples Duverger's law

in uk there no president , no unifying election force party mergers , regional 2 party systems formed. because duverger s law says number of viable parties 1 plus number of seats in constituency. in scotland, labour , snp 2 dominant parties. snp has replaced lib dems in role. in southwest england, lib dems face off against conservatives. labour voters vote lib dems prevent conservative winning. caroline lucas of green party has held seat since 2010.

other parties have won seats, either elected outside england, british fptp system used in parallel welsh , scottish proportional-representation multiparty democracy, or through by-elections (such respect coalition). northern ireland has entirely separate political system in neither labour nor liberal democrats stand candidates, conservatives not competitive.

riker pointed canada s regional politics, u.s. presidential election of 1860, examples of temporary regional instability occurs time-to-time in otherwise stable two-party systems (riker, 1982). in case of canada, highly regionalised parties evident in province-by-province examination: while multiparty system can seen in canadian house of commons, many of provinces elections dominated two-party systems. quebec, instance, driven sovereigntist, center-left parti québécois , center-right liberal party, while in saskatchewan, left-wing new democratic party , centre-right saskatchewan party (a coalition of affiliated conservative , liberal parties). unlike in united states, 2 major parties organized , unified @ federal, state , local level, canada s federal , provincial parties operate separate organizations.