On the centennial of America’s entry into World War I, the reasons we went to war hold an eerie resemblance to issues facing our country today.

One hundred years ago today, the United States officially declared war on Germany and entered World War I. Days before the declaration of war, President Woodrow Wilson urged a special joint session of Congress to “formally accept the status of belligerent which has thus been thrust upon it.”

Wilson had not wanted to do this. Indeed, he’d won reelection the previous fall as the antiwar candidate, running on the popular slogans “He kept us out of war” and “America First”—appeals to voters who wanted to stay out of a major European war and avoid a simmering conflict with Mexico.

But two events would change everything, and force Americans to accept that they could no longer avoid what had become a global conflict. The first was Germany’s resumption of unrestricted submarine warfare on passenger and merchant ships. The second was the “Zimmerman telegraph,” which revealed Germany’s attempt to forge a secret alliance with Mexico against the United States, promising to help Mexico recover territory it had ceded to the United States following the Mexican-American War in 1848.

Both of these developments, like much of World War I, seem exotic and unimaginable today. A major military power attacking passenger ships with submarines? Mexico invading Texas? It’s easy to think we’ll never face such scenarios again, and we probably won’t face those particular scenarios. But as distant and strange as the First World War seems to us today, the reasons Wilson changed course and declared war hold vital relevance to our national life in the twenty-first century, and we ignore or misunderstand those reasons to our peril.

Wilson Wanted To End European Imperialism

First, it’s necessary to understand why Wilson was opposed to declaring war. When World War I broke out in August 1914, Wilson promptly issued a declaration of neutrality. He wanted America to be in a position to mediate between Europe’s belligerent powers and bring about a peaceful end to the war. But he worried that Americans, most of them descendants of the European countries now at war, would be “divided in camps of hostile opinion, hot against each other, involved in the war itself in impulse and opinion if not in action.” If Americans did not embrace the “true spirit of neutrality,” it would undermine Wilson’s plan for the United States to play the part of impartial mediator.

His insistence on neutrality also arose from a deep conviction that American involvement could not bring about peace in Europe. Wilson, like many of his countrymen, believed Europe was going through a civil war, just as America had done a generation earlier. Wilson himself, born in 1856, as a boy had watched Gen. Robert E. Lee march his army through Wilson’s hometown of Staunton, Virginia, after the surrender at Appomattox, and he witnessed the devastation of Reconstruction firsthand. Wilson feared American involvement in Europe’s war would upset the fragile equilibrium America had managed to maintain since the end of the Civil War.

In addition, there was the matter of global imperialism. Wilson was a southerner—the first southerner to be elected president since 1848—but he was also a progressive, and one of the overarching goals of American progressives in that era was to keep at bay the disruptive social forces and ideologies that were emerging with the new century. Chief among those ideologies were the Great Power rivalries attendant to global imperialism.

Wilson, unlike American imperialists such as Teddy Roosevelt, wanted nothing to do with imperialism. In fact, his goal upon entering the war was not to ensure that Germany lost and the Allies won. His goal was “peace without victory,” because victory, in his view, would only perpetuate European imperialism by preserving Great Power status for the victors. Before the United States entered the war, Wilson had said taking sides would be a “crime against civilization” because any peace that resulted would be “forced upon the loser… and would leave a sting, a resentment, a bitter memory upon which terms of peace would rest, not permanently, but only as upon quicksand.”

His view of the matter didn’t change when America declared war on Germany. Instead of forcing peace on the loser, Wilson wanted the United States to force peace on all of Europe. He wanted nothing less than to break the back of Europe’s empires—not just Germany but also Britain, France, and Russia. This is what he meant when he said, “The world must be made safe for democracy.” He might as well have said the world must be made unsafe for empires.

WWI Clarified America’s National Interests

America’s entry into World War I marked a sea change for the country. The United States had never been an empire like Britain or France, but Americans did have a growing sense of their place on the world stage and what America’s vital national interests might be.

Germany’s resumption of unrestricted submarine warfare and the release of the Zimmerman telegraph were less than a month apart. The combination of these two developments galvanized American support for war against Germany, not for conquest but to defend the national interests. Then as now, those interests had to do with border security and free trade.

The Zimmerman telegraph proposed a secret alliance between Germany, Mexico, and Japan in the event America entered the war against Germany. Specifically, it promised that Mexico would be given Texas, Arizona, and New Mexico. The point, for Germany, was to persuade Mexico to declare war on the United States and tie American troops down on the U.S.-Mexico border, making it impossible for them to assist the Allied powers in Europe.

It wasn’t inconceivable that Mexico would declare war. After all, U.S. troops had been stationed in Mexico from March 1916 to February 1917 as part of the so-called “Punitive Expedition” against the paramilitary forces of Pancho Villa, which had launched numerous cross-border attacks against U.S. settlements in New Mexico and Texas, fomenting revolution on both sides of the border.

Mexico was of course in the midst of its own civil war, and in April 1917 the United States had not yet even recognized the government of Mexican President Venustiano Carranza. Although Carranza turned down the German offer, the revelation that such an offer had even been considered was a scandal to many Americans.

At the same time, German submarines were targeting U.S. merchant ships, sinking five that March. As a result, many U.S. ships were being kept in port, and Americans were outraged. The sinking of these ships, like the 1915 sinking of the Lusitania that killed more than 1,200 people including 128 Americans, was seen as a direct challenge to America’s rights as a neutral country.

These two factors, the integrity of our southern border and the rights of free navigation and trade, were ultimately enough to push a largely pacifist America and a deeply reluctant President Wilson into World War I. These events clarified American national interests for Wilson and the general public, and made manifest the need to declare war.

Today, we’ve lost clarity on our national interests. We rarely speak of them in concrete terms. This can be dangerous. As we face growing tension over our southern border and uncertain trade relations with major global powers, it’s worth thinking about the momentous decision we made a hundred years ago. It’s worth asking ourselves, again, what our national interests really are, and what we’re prepared to do to secure them.