As British Prime Minister Keir Starmer faces calls to resign for his appointment of Epstein-tied Peter Mandelson as ambassador to the United States, one is struck by the sudden instability of British governments. In the 28 years between 1979 and 2007, Britain had only three prime ministers, while in the 19 years since 2007, it has had seven, and may soon have eight. Only one of those, David Cameron, carried his party to a reelection victory, and he resigned a year after being beaten in the Brexit referendum.

It’s not just leaders who have stumbled. Even historically long-lasting parties have. Britain’s Conservatives, who, since the party’s founding in 1846, 180 years ago, have been the most electorally successful party anywhere, are polling at 19% today. So is the Labour Party, founded in 1900 and Britain’s second party since 1923, 103 years ago.

Similarly, elsewhere in Europe, France’s historic socialist, communist and Gaullist parties have more or less disappeared, and the National Rally, dismissed as unthinkable, to the point that the judicial establishment disqualified it from the ballot, still leads the polls under its 30-year-old successor.

Germany’s Social Democrats, founded in the 1880s, were swept in and promptly swept out of office, while the Christian Democrats, the descendants of the anti-Nazi Catholic Center party, have barely been holding their own against the oft-denounced AfD.

Italy’s dominant asymmetric duo, for two generations after World War II, the Christian Democrats and the Communists, fell on bad times in the 1990s, with the fading of belief in their founding faiths, Catholicism and communism. Dominant since then have been media millionaire Silvio Berlusconi, the Five Star Movement party, founded by a comedian, and the current prime minister, Giorgia Meloni, whose party’s roots were once dismissed as neo-fascist.

The two American political parties, the oldest and third-oldest in the world, have shown more stability. In the first half of the 20th century, Democrats survived the landslide rejection of Woodrow Wilson in 1920, and Republicans survived the landslide rejection of Herbert Hoover in 1932.

The two parties’ resilience prevented Americans from succumbing, as many feared they would, to the totalitarian temptations that swept much of continental Europe in the 1920s and 1930s.

In the volatile years after what was then called the Great War, communists took over Russia in 1917 through 1920, fascists took over Italy in 1922 through 1924, and Nazis took over Germany in 1933 through 1934. No one could be sure that a similar upheaval would not succeed in France, Britain or America.

Before that war, American presidents opposed restrictions on immigration, confident that assimilation efforts, such as big-city public schools and Henry Ford’s English-language classes, would Americanize the Ellis Island generation of 1892-1914. Fears of revolution and the wartime capacity to control people’s movements led to bipartisan majorities for the 1924 law that cut off immigration from eastern and southern Europe.

Now, a century later, immigration is the problem that, more than anything else, is threatening the hold of longstanding political parties. Old parties’ leaders in Britain and Europe, nervous that below-replacement birth rates would halt economic growth and endanger their welfare states, encouraged massive immigration of Muslims from North Africa, the Middle East and Pakistan. Prime example: former German Chancellor Angela Merkel’s unilateral decision, without consultation internally or with European Union partners, in 2015 to admit 1 million mostly male Muslims to Germany.

Police authorities and established journalists suppressed evidence that many migrants lived off welfare rather than productive labor, and that many such men felt justified in raping headscarf-less young women and beating up gay men. It has come to the point that British authorities are arresting and prosecuting citizens who send private emails that are thought to be unwelcoming to some immigrants.