Playing what-if with history is always good sport and oftentimes enlightens. Change one variable that plausibly could have been changed, project the impact of that change on the sequence of events that followed, and you can shine a spotlight on society or individuals at a particular time in a particular set of circumstances. In the process, you can have some fast and furious arguments with stakes that amount to zero—and enrage the purists among historians who demand we stick to documented facts. What’s not to like? Let merriment ensue!

For example, it’s been a century since Theodore Roosevelt died a premature death. The former president—who styled himself “Colonel Roosevelt” after departing the White House, to evoke memories of his Rough Rider days during the Spanish-American War—perished from an embolism. Physicians judged the blood clot delayed the effect of a fever he contracted in 1914 while slogging through the rainforest along Brazil’s Rio da Duvida, or River of Doubt.

TR was only sixty when he shucked off his mortal coil. But what if he had never set out to chart an unexplored river in the Amazon backcountry? He could have gone exploring in more healthful climes to numb the pain of defeat in the 1912 presidential election. Or what if he had disappeared into the Brazilian wilds but his renowned physical vigor—on one occasion in 1912 he finished a speech after absorbing a gunman’s bullet—had empowered him to withstand the fever’s assault? Such badassery would have been entirely in character.

History may have taken a different trajectory had TR made one minor decision differently—and lived another decade or two. This is an entirely defensible foray into alt-history.

Start with the obvious: would Colonel Roosevelt have run for the presidency again had he remained among the quick, and would he have triumphed if he did? Yes: he might well have stood for office again. He honored the two-term precedent set by his hero George Washington, but he regretted interpreting his first term—when he succeeded to the presidency by virtue of William McKinley’s assassination—as his first term rather than as the completion of McKinley’s term.

Washington was elected twice, while TR was acutely conscious that he was only elected once, in 1904. He longed to try again and believed he could do so honorably. Running and winning in 1920 would have delivered the satisfaction he craved. But purpose, not mere vanity, would have propelled him back into presidential politics. He had spent his post-presidential years vilifying his handpicked successor, the Republican William Howard Taft, and especially the Democratic victor of 1912, Woodrow Wilson. Doubtless, he would have regarded it as his calling to repair what they had messed up in domestic politics—and to correct Wilson’s botching of war and peace in Europe.

Would he have prevailed over the Republican candidate for 1920, Senator Warren G. Harding of Ohio, and the Democratic candidate, Governor James M. Cox, also of Ohio? It’s tough to envision TR’s garnering the Republican nomination after he had split the Republican vote and cost the party the White House in 1912. Memories run long, and so do grudges. He ran on the Progressive or “Bull Moose” ticket that year, and Republican Party bosses never forgave him for it. They probably would have thrown their backroom support behind Harding the way they had abetted Taft—and scotched any effort by Roosevelt to return to office as a Republican.

Which would have left another third-party run, presumably at the head of a rejuvenated Progressive Party, as his only option. But Harding crushed Cox on a campaign promise to “Return to Normalcy” after the Great War. This bland platform resonated with an electorate whose mood had soured after the war. “Devil theories” were starting to sprout. Those who played the blame game, that is, faulted munitions makers and other shadowy malefactors for goading Wilson and the Democratic Congress into joining the fighting. And they had done so for the sake of profitmaking—a suspect motive at best. Since Democrats had been in charge when America marched off to war, voters likely would have punished them for succumbing to sinister interests. The people would have exacted vengeance at the ballot box.

In short, it’s doubtful 1920 would have witnessed a replay of 1912, when a Democrat slipped into the White House by virtue of divided opposition. But it’s likewise doubtful a third-party Roosevelt would have again defeated the Republican candidate, as he had Taft. While the Colonel retained his personal popularity, America was a different place in 1920 than it had been in 1912. If the electorate held Democrats responsible for sending doughboys to the Western Front, well, TR had spent the war years flaying Wilson for being too slow to take up arms and for waging war too feebly once he did. If Wilson was guilty of being a reluctant warrior, TR may have been entirely too eager a warrior for cynical times.

If the American people pined to return to normalcy, Theodore Roosevelt was anything but normal. My best guess: once again the Bull Moose would have placed second in a three-way contest. If so, he probably would not have essayed a return to office a third time. In all likelihood, he would have remained a public figure. However, he would have held forth from the pages of books, magazines, and newspapers rather than his bully pulpit in Washington, DC. In private life, the written word would have remained his best implement for shaping public opinion in favor of his political and strategic vision.

But this is alt-history. Suppose he did prevail. The Colonel was a gifted politician and orator, he abounded with charisma, and he had beaten the odds before. Maybe he would have adapted to the times, distancing himself from his wartime advocacy and fashioning an appeal that won over voters. Rather than pledge to Return to Normalcy, perhaps he could have outdistanced Harding with a vow to “Return to Progress” or some such slogan.

Then what? In domestic policy, President Roosevelt v2.0 surely would have pursued social reform, trust-busting, and the litany of causes he held dear. Yet unless Progressives somehow managed to storm the Capitol—winning a congressional majority against long-established parties—he would have found legislating far more difficult than during his 1901–1909 term. Neither Republicans nor Democrats would have felt beholden to a Progressive chief executive. The risk of a do-nothing Congress would have loomed. Warding off stasis would have demanded the full measure of statesmanship from TR.

The same might be true of foreign policy, although presidents enjoy a freer hand in the international realm than at home. President Roosevelt would have inherited the residue of World War I. Congress, of course, had abstained from ratifying the Treaty of Versailles, the compact terminating the fighting. Lawmakers also refused to take the United States into the League of Nations Covenant, and thereby join the world organization the Allies had framed to keep the peace.

What would TR have done with the postwar settlement, the handiwork of the despised Woodrow Wilson? Roosevelt was no foe of a world body in principle. In fact, he had espoused a “League of Peace” long before Wilson bruited about the League of Nations. But TR would have structured his League of Peace differently from the League of Nations, restricting membership to like-minded powers—chiefly the wartime Allies. That would have bolstered the prospects for consensus and common action to fend off peril. He also contemplated equipping the league with its own judiciary backed by its own armed forces for executing police actions.

The Versailles Treaty and League Covenant took effect in January 1920, well before that year’s U.S. presidential election, so it’s hard to see how President Roosevelt could have revised the settlement to conform to his preference for muscular peace enforcement. Whether he would have spent political capital to persuade Congress and the populace to embrace the arrangements as they existed is an open question. Color me skeptical. TR scorned international accords that were unenforceable, while he prophesied that the time was “eons distant” when nations might unite in some sort of federation to preserve global concord. Consequently, he probably would have remained aloof from the flawed settlement to World War I rather than renew Wilson’s futile “treaty fight” with lawmakers. That’s doubly true if I’m right about his weak standing vis-à-vis Congress.

Let’s close with maritime affairs. How would President Roosevelt have approached an age of naval arms control, and how would he have handled a U.S. Navy that, unlike his modest Great White Fleet, had achieved the stature of a “navy second to none”? In all likelihood, he would have welcomed overtures aimed at curbing a naval arms race among the Western great powers and Japan.

That’s because sufficiency—not global supremacy—represented TR’s watchword in naval strategy and fleet design. Like his sometime friend and confidant Alfred Thayer Mahan, he had long contented himself with a twenty-battleship fleet. Not because that made the U.S. Navy the world’s biggest—far from it during the age of British naval primacy—but because a fleet that size could stand against the largest fraction of a hostile navy that some foreign government might dispatch to the Americas to make trouble for the United States. An American fleet massed in home waters could overpower a fragment of a larger rival navy. That was sufficient.