to introduce universal suffrage, the progressive liberals favoured universal suffrage, the conservative liberals did not. The progressive liberals also favoured government intervention in the economy, such as Van Houten's ban on child labour. Due to the two round electoral system the liberals were required to cooperate. In order to prevent the coalition of Catholics and Protestants win the second round of the elections, all the liberals united behind their candidates in the second round, often joined by social democrats. This alliance was called the concentration. On basis of concentration pluralities, often supported by social democrats for a majority several cabinets were formed in the early 20th century. In 1917 under one of these liberal minority cabinets universal male suffrage was introduced, as well as a proportional electoral system and equal finance for religious schools, this compromise was called the pacification of 1917. The extension of suffrage however severely weakened the position of the liberals. Of the 37 seats they had in 1917, they were left with 14 in 1918. 1918-1994 In 1922 the liberal parties reorganized: all conservative liberals, from the Liberal Union and the League Free Liberals as well as more conservative liberals from smaller parties, joined to form the Liberal State Party. The progressive liberals remained separate in the Freeminded Democratic League, a merger of the Radical League and progressive liberals, that had already been formed in 1901. In the interbellum the liberals grew even smaller. Under pressure of the Wall Street Crash of 1929 and the rise of the National Socialist Movement. The liberals did cooperate as junior partners in several cabinets in the crisis. After the Second World War the conservative liberal Liberal State Party refounded itself as Freedom Party. The progressive liberal Freeminded Democratic League joined the new Doorbraak leftwing Labour Party. Several progressives were unhappy with the social-democratic course of the PvdA and joined the Freedom Party to found the People's Party for Freedom and Democracy in 1948. The VVD remained a small party until the 1970s, with about 10% of the vote. They did however form part of the government both in the grand coalition with social-democrats, Catholics and Protestants in the late 1940s early 1950s, and with the Catholics and Protestants over the course of the 1960s. The party was led by the former leader of the Freeminded Democratic League, Pieter Oud. In the Dutch pillarized political system the liberals mainly appealed