The Liberal Party once was one of Great Britain’s two great governing parties. A century ago it self‐​destructed. On December 5, 1916, H. H. Asquith, the prime minister since 1908 who took his country into World War I, resigned. That effectively ended the role of the Liberals, who were moving from classical to modern — substituting statism for freedom as a driving force of British politics.

Although his successor, David Lloyd George, was also a Liberal and who led a coalition government with the Tories, the party was wrecked in the election held in 1918 at the conflict’s conclusion. Lloyd George’s Conservative Party partners soon defenestrated him, after which the Labour Party came to dominate the Left. The Liberals survived as a minor force, through a merger with the Social Democratic Party later yielding the Liberal Democrats, who served in coalition with the Tories from 2010 to 2015. The LibDems, as they now are known, have abandoned their classical liberal roots and now are the Left’s minority partner of choice.

Asquith well deserved his political death. While presiding over a leftward shift in the Liberals, he thoroughly botched the Irish question, the challenge of home rule and independence, which yielded brutal civil conflict and veritable civil war. Far more important, however, he presided over a deteriorating relationship with Germany, hid from Parliament and even the Cabinet the development of a de facto alliance with France, and made the disastrous decision to enter World War I.

The result was catastrophic for his country: close to 900,000 dead and 1.7 million wounded, many with debilitating injuries. The war drained Britain’s economic strength, acting as the beginning of the end of London’s role as a global power. The Versailles Treaty, which concluded what was originally known as the Great War, proved to be just a generational armistice as the combatants prepared for round two. World War II was the result, which finished off Great Britain’s international pretensions.

Globally the impact was even greater. Top estimates of total deaths exceed 21 million. The number of injured approached 24 million. Three liberalizing monarchies — Wilhelmine Germany, Austria‐​Hungary, and the Russian Empire — were destroyed. The malignant totalitarian viruses of fascism, communism, and Nazism were released. The Versailles Treaty made a hash of President Woodrow Wilson’s high‐​sounding principles: Lloyd George and French Prime Minister Georges Clémenceau ruthlessly outmaneuvered the sanctimonious and uncomprehending Wilson.

Instead of ending the possibility of war, the major powers used the treaty as an opportunity to plunder the defeated nations and acquire new colonies (in the name of “mandates”). Toward Germany the victors fell unsatisfactorily between imposing a Carthaginian peace and engagement. Wilson gave up everything else to win acceptance of his League of Nations — yet America never joined and the organization ultimately flopped. Italian Prime Minister Vittorio Emanuele Orlando spent most of his time sulking, angry that his partners denied his extravagant compensation claims for military participation that proved to be little short of disastrous for his people and allies alike. (As in World War II, Rome’s friends came to wish it was fighting on the other side.)

The conflict was completely unnecessary. Germany’s Iron Chancellor, Otto von Bismarck, had created a united Germany while holding his nation’s adversaries apart. His successors, chosen by the vainglorious, boastful Kaiser Wilhelm II, were not so deft. Two contending alliances emerged. Neither was particularly attractive. The Entente included Great Britain, the globe’s greatest colonial power; Imperial Russia, an anti‐​Semitic despotism; and France, a humiliated, revenge‐​minded democracy. The Central Powers were Imperial Germany, an ambitious semi‐​democratic state with a broader franchise than Great Britain but authoritarian constitutional structure; Austria‐​Hungary, a ramshackle, inefficient, antiquated monarchy; and Italy, a faithless democracy, willing to sell its participation in war for the promise of territorial reward.

An act of state terrorism, the assassination of the heir to the Austro‐​Hungarian throne by Serbian military intelligence, lit the fuse to a global military explosion. Rather than act as barriers to conflict, the alliances turned into transmission belts of war. All the powers were convinced that their adversaries would back down. All presumed that the conflict would be short and they would win.

The Kaiser did not want conflict with London. Germany was satiated, hoping to hold onto its past gains. In contrast, France was a revanchist power, determined to retake the territories of Alsace and Lorraine, seized by Berlin some four decades before in the Franco–Prussian War. To this end, Paris turned the Franco–Russian alliance into an offensive instrument, applicable even if its members started the war.

Britain’s Liberals traditionally opposed imperial misadventures. But the party was changing, and Foreign Minister Edward Grey committed to the Entente even though both France and Russia were traditional enemies. Without cabinet or parliamentary approval, Grey, initially without Asquith’s knowledge, essentially promised that London would go to war with France — and failed to make that prospect clear to Berlin. Alas, Germany had done much, most importantly attempting to build a navy to match Britain on the seas, to squander British goodwill and reinforce the latter’s concern for the continental balance of power.

There also were political considerations. The Liberals were an internationalist party whose members reviled Berlin’s decision to attack France through neutral Belgium. (Many were equally uncomfortable allying with Tsarist Russia.) Moreover, the Tories emphasized nationalism and patriotism, sentiments easily inflamed as conflict threatened. The Liberal Party felt pressure to match the Conservatives, and going to war seemed politically popular.

Asquith recognized the stakes, observing that “We are within measurable, or imaginable, distance of a real Armageddon.” There was substantial Liberal Party opposition to the decision to join the continental killfest, but Asquith wanted to preserve the continental balance of power and decided to back Grey. The government was able to minimize the public impact by basing its decision on Germany’s violation of Belgian neutrality. In fact, until the year before the French military was prepared to invade Belgium to outflank Germany, but Paris ultimately demonstrated greater political sensitivity and changed its war plan. Only two leading Liberals, John Morley and John Burns, resigned from the cabinet.

Unsurprisingly, joining what turned out to be the worst conflict in human history ravaged the Asquith government’s domestic agenda. Any lingering opposition to burgeoning state power dissipated. Most important, London abandoned its tradition of raising its military voluntarily. The prodigious killing quickly destroyed the initial expeditionary force sent to the continent. Enthusiasm among potential recruits for becoming cannon fodder waned. Efforts to shame young men into volunteering for what seemed like suicide duty to advance imperial ends faltered. So Asquith betrayed his party’s fundamental principles and pushed legislation inaugurating conscription.

His government came under attack for military blunders and inefficiency. Asquith, who lacked a solid parliamentary majority, lost political support. Barely a year into the war, he was forced into a coalition with the Conservative Party. A year later he was gone, the victim of an ever‐​bloodier war and devious political intrigue by his erstwhile colleague Lloyd George, among others.

Asquith carried on as the loyal opposition leader during the rest of the conflict. Lloyd George called an election after the armistice ended the fighting in November 1918, when Asquith and the opposition Liberal Party members were routed. The former prime minister and his original Cabinet ministers all were defeated; even Labour won more seats than did Asquith’s Liberal faction. He returned to Parliament in a by‐​election in 1920. Two years later, the Tories tossed Lloyd George overboard; the succeeding election returned more members of Labour than both Liberal Party groupings combined. The 1924 election cost Asquith his seat to a Labour Party candidate and reduced the Liberals to a rump faction, finally ending their political significance. By the 1970s, the party was lucky to win a dozen seats. It revived slightly as the hybrid Liberal Democratic Party, but only a hung parliament is likely to give it any practical role.

The war cost Asquith personally as well. One son, Raymond, was killed, and another, Arthur, was severely wounded, losing a leg. In this regard, at least, the premier paid the same price as many of those he governed. In those days elites could not so easily escape the consequences of their poor political decisions.

The 20th century would have been very different had Prime Minister Asquith chosen to keep his country out of World War I. He would have retained power. His party would not have been effectively absorbed by the Tories, leaving the more radical Labor Party as the primary force on the left. Today the entire political spectrum might sit further to the right, with Conservatives something more than moderate American Democrats and the Liberals offering a leftish critique without pushing the Labour Party’s nutty dream of nationalizing industry.

Britain likely would have remained a great power for years, if not decades, its economic strength only slowly ebbing as the U.S. less dramatically emerged as global No. 1. Washington would not have entered a conflict with little relevance to its own security and dramatically unsettled the European balance of power.

Germany probably would have won a much shorter conflict, which might not even be known as a world war. That would have been bad for French prestige, but far fewer of its soldiers would have died, and little of its territory would have been devastated by trench warfare. Russia would have been forced to make peace before revolutionaries had toppled the House of Romanov and created the first Bolshevik state. Austria‐​Hungary also would have survived, along with Hohenzollern rule in Germany. Whatever would have ultimately emerged in those states would not have been communism and Nazism. Peace would not likely have been eternal, but whatever happened probably would not have been anything resembling World War II.

We see through a glass darkly, the Apostle Paul observed. Like so many other European policymakers in the summer of 1914, Asquith did not understand the forces that he was unleashing or the likely consequences of doing so. When he resigned 16 months later, perhaps he saw more clearly the imminent destruction of his political career and the more distant decline in his nation’s power. But then it was too late to halt Europe’s and the world’s destructive course.