The best government is government by consensus. In western industrial democracies this means government by a coalition with the Prime Minister or leader as the the chairman. When there are just two major parties as there are in the UK, Canada or the USA, it is often the party which often may have more members than the other parties but which may still not have  majority of the votes which wishes to avoid a coalition. That is too much power for the one party and when the party whip is applied it means the leader has more power than is warranted by the number of votes his party received. That is why some party leaders want to keep the first past the post system and wish to avoid proportional representation.<br>With a coalition a party leader would have to appoint to his cabinet members of other parties and decisions represent more closely the feelings of the electorate rather than the feelings AND IDEAS OF ONE PARTY. The Canadian health service was instituted with the the votes of two parties against the wishes of a third party. The Liberal Party did not have a parliamentary majority. If it did have it is likely the health service would NOT have passed into law.<br>Polls tell us that most Americans would like a universal health care system but they don't have it because there are only two parties, decisions are made by lobbyists and the power of money prevents truly democratic decisions. A multiparty system with the power of money and of lobbyists reduced would make for more democratic decisions. Part of the problem of course is the antiquated system with the electoral college instituted by the founders in the days of slavery shortly after the country became divorced from the colonial power, Great Britain.<br>In Canada one party included a proportional voting system in its party platform but the leader, Mr. Trudeau, fearing a diminution of his power, decided along with his cabinet of strictly party members to go against the wishes of the people who elected the party and the appropriate legislation was not introduced into parliament. In the next election Mr. Trudeau' party was re-elected  but WITHOUT a working majority.<br>WHEN A PARTY AND OFTEN ITS LEADER HAS ABSOLUTE POWER THERE CAN BE PROBLEMS.  THE NEXT GOVERNMENT MAY REVERSE LEGISLATION OF A PRIOR GOVERNMENT AND SOMETIMES DOES. This has happened in the USA where Trump has reversed many good decisions made by President Obama.