We struggle to explain the rise of the far right in its various guises. Immigration is important, but the dynamics predated the refugee crisis. The euro crisis has not helped. High unemployment is crucial in France and Austria, but not an issue in Britain. Chaos in the Arab world, following the fiasco of the American-led invasion of Iraq, fuels new Middle East wars and terrorist attacks in Europe, adding to feelings of insecurity. Globalization, the loss of middle-class jobs, the rise of inequality and anxiety over the European social model have left immense frustration. Everywhere, anger toward ruling elites and mainstream institutions is patent.

Sound familiar? Yes, this is a trans-Atlantic phenomenon. Here and there, surfing on this anger, Donald Trump, Boris Johnson or Marine Le Pen utter statements that would have been unthinkable 10 years ago. By accepting daily verbal assaults on immigrants (“They bring disease”), the European Union (“like Hitler,” it wants to impose one authority over Europe), Islam (not part of Europe; Muslims should not be allowed into the United States), torture (bring it back), we are legitimizing a public discourse that may, one day, translate into political decisions.

Like most European center-right or center-left leaders, President Obama understands this. On the day after the first round of Austria’s election, he warned in a speech in Hanover, Germany, against “the creeping emergence of the kind of politics that the European project was founded to reject: an us-versus-them mentality that tries to blame our problems on the other.”

“Our progress,” he pointed out, “is not inevitable.”

As multiple forces rip apart the liberal order, what is lacking from Washington, though, is an acknowledgment of the global and historic dimension of this phenomenon. This is not only about Europe. The symptoms that characterize the rise of Trumpism are the same as those of “the creeping emergence” Mr. Obama described. Recently, Pope Francis urged leaders to “update the idea of Europe.” Well, the broader idea of the West also badly needs an update.

On Aug. 14, 1941, with Europe engulfed by war, Franklin D. Roosevelt and Winston Churchill met aboard the American cruiser Augusta and drafted the Atlantic Charter. This brief statement established eight common principles on which the two leaders based “their hopes for a better future of the world.” For decades, those principles, among them “freedom from fear and want” and “improved labor standards, economic advancement and social security,” would be seen as the inspiration of the free world. These were brave, progressive goals then. Now they deserve an update.

President Obama, we are told, is working on his legacy; visits to Cuba and Hiroshima are certainly appropriate. But there is another mission to embark on with Europeans. Or the man celebrated in 2008 as the first black American to be elected president will risk going down in history as the last American leader to preside over a Western democratic order.