Prof. Ofer Kenig presents examples of parliamentary democracies in which the Prime Minister is from a small party.
"Prime ministers in parliamentary democracies most often come from large parties, but the possibility of a government headed by someone from a small party certainly exists. In Belgium and Latvia prime ministers representing smaller parties now serve in office. Such a situation usually occur in circumstances where the political system is at a dead-end and a compromise candidate is appointed. While this is not an ideal situation, it may be preferable to the reality of prolonged political deadlock."Prof.Ofer Kenig
• The current Prime Minister Alexander de Crooo (incumbent since October 2020) serves on behalf of the Flemish Liberal Party (Open VLD) even though his party won only 12 seats out of 150 (8%) in the last election. It is the fifth largest party in parliament ... even if we include the Walloon Liberal Party (MR), which is considered a "sister" party, they both hold only 26 seats (17%).
• Also, following the 2014 elections, a prime minister was finally appointed from a mid-size party. Charles Michel served on behalf of the Walloon Liberals (MR) even though they received only 20 seats (13%) which placed them as the third largest party.
• The current Prime Minister Arturs Krišjānis Kariņš is serving on behalf of the New Unity List (JV) which in the 2019 election received only 8 seats (8%) which placed it as the smallest party in Parliament! Following the failure of major party candidates to form a government after the election, the president gave Kariņš a chance and he managed to form a coalition of 5 parties.
• Giovanni Spadolini served as Prime Minister of Italy for a year and a half (1981-1982). He served on behalf of the Italian Republican Party (PRI) - a small center-right party that won only 16 seats out of 630 in the election (2.5%). In fact it was only the fourth largest partner in a coalition of 5 parties. Coalition parties decided to appoint him after the previous prime minister (on behalf of the Christian Democrats) resigned amid a corruption scandal.
• Benedetto "Bettino" Craxi served as Prime Minister from 1983 to 1987. He represented the Italian Socialist Party (PSI) - a medium-sized party that won 73 seats (about 12% of all seats). It was the second largest party in a coalition of 5 parties, but the major party relinquished the post of prime minister.
• Giuliano Amato served as Prime Minister for one year (1992-1993).He served on behalf of the Italian Socialist Party (PSI) - a medium-sized party that won 92 seats (about 15% of all seats). It was the second largest party in a coalition of 4 parties.
Ahti Karjalainen served as prime minister for a year and a half (1970-1971) on behalf of the Center Party (KESK) - a party that came only third in the election with 36 seats out of 200 (18%). The party was the second largest in a coalition of 5 parties.
• Martti Miettunen served as Prime Minister for a year and a half (1975-1977) on behalf of the Center Party (KESK) - a party that came only third in the election with 39 seats (19.5%). The party was the largest in a minority government formed after a deadlock in forming a government.
• Kjell Magne Bondevik served as Prime Minister for two and a half years (1997-2000) on behalf of the Christian Democratic Party (KrF) even though in the election it came only in fourth place and won 25 seats (15%). He returned to office after the 2001 election, although in this election the party came only in fifth place and won only 22 seats (13%).