Kaiser Wilhelm II was far from the absolute monarch of the German Empire, despite Allied World War I propaganda that still resounds today. Instead, like Donald Trump in our own time, Wilhelm became chief executive of an overcentralized, personalized system where his idiosyncratic behavior (and extravagant hairstylings—for Wilhelm, a mustache) smashed norms. For Germany and the western world, all this worked—until it didn’t, with the start of World War I.

These days, the Great Man theory of history is out of fashion—yet a destabilizing personality can still upend institutions and relationships. Given Wilhelm’s long and colorful reign, a blow-by-blow account would approach the length of John C. G. Röhl’s definitive, three-volume, 3,884-page, 16.2 lb. biography of the man. Instead, we will narrow the focus, to look at Wilhelm as a disrupter of domestic and international systems.

He was born on a bad heir day. A difficult breech birth left Wilhelm with a useless left arm—the first thing that visitors noticed was his tiny hand. He spent his childhood wearing iron braces and doing painful, exhausting physical therapy, with little improvement. Photographers were instructed to avoid showing his hand, which was always concealed with a glove. Perhaps Wilhelm would have suffered fewer injuries at birth—he also likely suffered oxygen deprivation—if his father, Prince Friedrich Wilhelm, had sent for the obstetrician by messenger instead of regular mail.

Other aspects of young Wilhelm’s family situation were also unhappy. His mother Princess Victoria, daughter of the United Kingdom’s Queen Victoria, was Elizabeth Warren with a tiara: a rigid progressive. Not only was she repelled by her son’s disability, but Princess Victoria found his personality distasteful. She was not alone: His tutor worried about the “crystal-hard egoism” at “the innermost core of his being.”

As an adolescent, Wilhelm tried to connect with his mother, writing Victoria a series of letters about a recurring dream in which he fetishized her gloved left hand. His fetish continued in adult life—his handlers paid hush money to a woman professionally known as Miss Love, who possessed letters on his taste for hand bondage.

While Fred and Mary Trump hoped to improve their son’s character by enrolling him in a military academy, Friedrich Wilhelm and Victoria went the Tiger Mother route. Despite Wilhelm’s physical disability and a likely learning disability, they sent him to live for three years in the Spartan confines of a gymnasium (an academic high school), where he competed with far better prepared middle class students. Röhl’s biography reports:

The prince crammed from six in the morning until ten at night, including Saturdays: nineteen hours a week of Greek and Latin, six hours of mathematics, three hours of history and geography, three hours of German and two of English . . .

The physical discomforts and antiquated curriculum did little to educate the future monarch of an industrial giant, but much to embitter him.

In 1888, after the deaths of his 90-year-old grandfather Wilhelm I and cancer-stricken father within three months, the 29-year-old Wilhelm ascended to the throne. Pre-war Imperial Germany’s political system can be described (if it’s fair to do so at all) as a federal semi-absolutist aristocratic semi-democracy. The Empire consisted of several sovereign states, with Prussia by far the largest. These states even exchanged ambassadors. Each had its own executive (Wilhelm as King of Prussia) and parliament. At the imperial level, the Emperor appointed the Chancellor and a Cabinet which largely consisted of aristocrats. The popularly elected imperial Reichstag had urban/agricultural, east/west and Protestant/Catholic/Socialist splits.

Otto von Bismarck claimed that Germany under Wilhelm I was the Emperor’s personal monarchy, a form of government superior to Western Europe’s constitutional monarchies. In reality, Bismarck, as Chancellor (and also Prime Minister of Prussia) was the key figure, employing a combination of compromise, bullying, and parliamentary management.

Unlike his grandfather, Wilhelm II expected to rule and not reign, modeling himself on Prussia’s 18th-century Frederick the Great: “I am the sole master of German policy and my country must follow me wherever I go.” Röhl observes that his portraits were “in martial pose, with an oversized field marshal’s baton and a defiant expression.” A man of vociferous opinions, few consistent, he was confident of his universally superior knowledge. His confidence was not matched by an ability to read briefing materials or master policy details.

The Emperor had absolute power over appointments to his cabinet. Soon after Wilhelm’s accession, at the urging of personal advisors outside the government, he began disrupting Bismarck’s administration. Without the Chancellor’s approval (which the constitutional system required), Wilhelm suddenly intervened in a miners’ strike, ordered abandonment of a Russian bond transaction, and issued proclamations on social policy. When, after huge losses in the 1890 Reichstag election, Bismarck began negotiating to dismantle his anti-Catholic Kulturkampf legislation, Wilhelm’s advisors saw a Bismarck-Jesuit-Jewish conspiracy. After summoning the 75-year-old Bismarck from bed in order to rage at him, Wilhelm unceremoniously dismissed the Iron Chancellor.

With Bismarck gone, Wilhelm installed nonentities in the Cabinet. General Georg Leo von Caprivi succeeded Bismarck despite his lack of diplomatic experience, and despite his lack of ties with the Emperor’s court, the landed aristocracy, or the Reichstag. The Cabinet (the “responsible government” in Imperial political parlance) still needed working relationships with the Reichstag, which had power over legislation and budgets. But Wilhelm’s eruptions made it difficult to finalize deals.

After pursuing “Social Kaiserdom” early on, the Emperor reversed course and advocated the violent suppression of what he considered revolutionary groups, particularly the primarily non-revolutionary Social Democratic Party (SPD). He told military recruits that he might order them to “shoot down and stab to death your own relations and brothers.” Germany’s free and highly competitive mass press served as the Twitter of the day, disseminating the incendiary language. According to SPD leader August Bebel, every sulfurous Wilhelm speech brought the party 100,000 more votes.

This chaos was unpleasant for those in the government. As Wilhelm’s closest friend and informal advisor, Philipp Eulenburg, wrote to the future Chancellor, Bernhard von Bülow:

Christopher Clark, a Wilhelm biographer and author of the neo-revisionist pre-World War I history The Sleepwalkers, argues that Wilhelm’s erratic interventions caused informal power in the system to gravitate away from him and toward the responsible government and Reichstag. This may have been true for domestic policy (the fin de siècle boom continued, and Germany’s civil liberties were largely unaffected), but is less persuasive for national security policy. This was legally the realm of the monarch and the aristocrats he directly appointed, with few checks.

By the time Wilhelm fired the Iron Chancellor, the international balance of power was roiled by Balkan nationalisms, Ottoman-Russian-Austro-Hungarian rivalries, the global race for colonies, and the rising industrial might of Russia, the United States, and Japan. Even Bismarck had found this increasingly difficult to manage, but Wilhelm, who anticipated a racialized final struggle between “Gallo-Slavs” and “Teutons,” made the international environment more fraught.

Early on, the Kaiser proved willing to overturn international agreements. Bismarck had entered into a secret Reinsurance Treaty with Russia up for renewal in 1890. After at first wanting to renew, Wilhelm suddenly terminated it, which helped drive Russia toward France.

Other interventions played out in diplomatic circles and in public. Wilhelm demanded an ill-defined “place in the sun” for Germany, echoing the current slogan of “America First.” In 1908, he provoked a German constitutional crisis by asserting his personal control of foreign policy in a rambling interview with Britain’s Daily Telegraph, filled with false assertions about other powers.

In another 1908 interview—this one with the New York Times—he asserted that the sooner that war came with England, the better. Bülow managed to prevent publication, but it became widely known among diplomats. Wilhelm frequently expressed hostility toward the United Kingdom, yet melodramatically raced to the bedside of the dying Queen Victoria in 1901. The joke, similar to the American joke about Theodore Roosevelt, was that Wilhelm “wanted to be the stag at every hunt, the bride at every wedding, and the corpse at every funeral.”

The Kaiser was also fond of sudden public appearances. In 1905, when the French, Germans, and British were contesting control of Morocco, Wilhelm unexpectedly arrived in Tangier, risking war. Yet at the subsequent Algeciras Conference, Berlin failed to provide instructions to the German delegation for months. He was more loquacious in an 1898 visit to Ottoman-controlled Jerusalem, entering the city on horseback in a field marshal’s uniform and supporting German protection of a Jewish homeland in Palestine, of Catholics in the Holy Land, and of a Lutheran church in Bethlehem, as well as declaring his friendship for Muslims throughout the world. As unsettling as the Ottomans found this, it was less grandiose than President Trump’s recent endorsement of a comparison to the King of Israel and the second coming of God.

Like the current U.S. President, Wilhelm avoided prior staff consultation. He preferred personal communication with the royals of other powers, such as the two-decade-long “Willy-Nicky correspondence” with Czar Nicholas II that the Bolsheviks revealed in 1918. And while his 1914 “blank check” to Austria-Hungary for military measures against Serbia is famous as a proximate cause of World War I, it was preceded by blank checks in 1895 and 1908.

Nor was the Kaiser shy about direct threats. In the decade before World War I, he told the Netherlands’ Queen Wilhelmina that he planned to occupy the Dutch coast in the event of war with France, and threatened two successive Kings of Belgium with invasion in that scenario. He threatened a naval war in King Edward VII’s presence in 1908, and told Prince Louis of Battenberg (a UK royal family member and senior UK naval official) in 1911: “You must be brought to understand in England that Germany is the sole arbiter of peace or war on the Continent. If we wish to fight, we will do so with or without your leave.” The German bureaucracy tried to soft-pedal Wilhelm’s statements, but officials in other countries questioned his sanity. Diplomats would have perceived a kindred spirit when Donald Trump threatened “fire and fury” against North Korea and bragged of his ability to wipe Afghanistan “off the face of the earth,” and “totally destroy and obliterate the economy of Turkey.”

The Emperor filled his national security establishment with people who shared his aggressive desires, resulting in Grand Admiral Alfred von Tirpitz’s naval arms race with the United Kingdom and the army’s Schlieffen Plan for a two-front war with France and Russia. The quality deteriorated as Wilhelm personally abused national security officials and promoted favorites. Groupthink contributed to inadequate resources for the grandiose plans, and to missed signals when UK officials indicated that they would stand by the Triple Entente with France and Russia.

The Kaiser made the national security establishment’s job harder with his impulsive and contradictory demands. As the 1914 crisis approached its final phase, with the military solidly in favor of war, he began waffling. Nonetheless, on July 19, he ordered the bombardment of Russia’s Baltic naval bases, followed by a July 27 order to blockade the eastern Baltic. On July 30, he ordered Chancellor Theobald von Bethmann-Hollweg to reach out to London with a security pledge to defuse the Austrian-Serbian crisis. Then, on August 1, he demanded that the planned Western Front offensive be abandoned and that hundreds of thousands of troops be moved to the Eastern Front. All these commands were deflected or ignored, and the invasion of Belgium began on August 4. Said Helmuth von Moltke the Younger, the Chief of the German General Staff: “I am happy to wage war against the French and the Russians, but not against such a Kaiser.”

Even before the Trump Administration, U.S. national security policy had uncomfortable parallels with Wilhelmine Germany. From at least the turn of the millennium, it has been dominated by Presidents who are served by a coterie of White House staff from the right schools or the right families. Presidents make heavy use of executive action without congressional approval and, thanks to claims of executive privilege, the White House staff is largely exempt from legislative oversight. When departmental bureaucracies offer independent perspectives, the White House staff can cut them out of the national security process. If the members of the German General Staff had tattoos instead of duelling scars, they might look like this.

Centralization allows Presidents to act on their messianic instincts: bringing the Pax Americana to the world for George W. Bush, ending the Pax Americana for Barack Obama and Donald Trump, and transforming the Middle East for all three. Like Wilhelm, Obama and Trump also felt free to undermine their respective predecessors’ policies, and even their own administrations’ policies, as with Obama’s sudden withdrawal and return to Iraq and Trump’s reversals on Syria. Political scientist Daniel Drezner worries that future Presidents may find it impossible to make a credible foreign policy commitment.

Kaiser Wilhelm suggests the risks of a personalized policy based on threats, bluffs and reversals—and the danger that foreign powers, reading United States policy seriously and literally, may take risks of their own.