Introduction

In the 1956 election to the French National Assembly, Pierre Poujade’s rightwing populist Union for the Defense of Traders and Artisans (UDCA) unexpectedly won 11.7 percent of the votes. It was one of several signs that the Fourth Republic was coming to an end. In 1966 a party named Democrats ’66 was founded in the Netherlands with the explicit goal to explode the, then extremely structured, Dutch party system and push for institutional reforms. It gained 4.5 percent of the votes in the 1967 election to the Second Chamber of the Dutch parliament. Six years later Denmark experienced a political earthquake, when the entry of new parties into the party system was accompanied by a sharp rise in electoral volatility. Most spectacular was the sudden rise of an anti-tax protest party, the Progress Party, founded in 1972, which emerged from the election as Denmark’s second strongest party. It secured 15.9 percent of the votes.