German Chancellor Angela Merkel took aim at Donald Trump’s world view in a speech on U.S. soil, saying unilateralism risks bringing down post-World War II alliances and trade wars threaten the “foundations of our prosperity.”

“More than ever, our way of thinking and actions have to be multilateral rather than unilateral,” Merkel said in a commencement speech to Harvard University’s class of 2019 that combined tough criticism of nationalist policies with philosophical vistas of a change for the better.

Merkel, 64, was addressing a receptive audience on Thursday as she seeks halt a deterioration in the trans-Atlantic alliance under Trump’s presidency. In her 14th year in office, officials in Merkel’s government are beginning to speak of a point of no return in U.S.-German relations.

At times, Merkel drew applause from the crowd by seeming to address the U.S. leader directly, urging graduates not to act “first impulses” or to brandish “lies as truth and truth as lies.”

Some 2,000 miles to the west, Trump reprised his America First doctrine in a speech to the U.S. Air Force Academy in Colorado Springs, Colorado, saying the U.S. won’t sacrifice its interests for those of foreign powers.

“We don’t do that anymore,” Trump told graduates. “In all things and ways we are putting America first. and it’s about time.”

German Chancellor Angela Merkel, center, waves as she is presented with an honorary Doctor of Laws degree as former Harvard President Drew Faust, left, and Harvard Provost Alan Garber, right, applaud during Harvard University commencement exercises, Thursday, May 30, 2019, on the schools campus, in Cambridge, Mass. (AP Photo/Steven Senne)

East German Past

Merkel, Germany’s first female chancellor, drew from her own biography as the daughter of a pastor who grew up in East Germany and rose from political obscurity after the collapse of the Berlin Wall and German reunification in 1990 to the country’s highest elected office.

Merkel joins a list of prominent commencement speakers in recent years, from Facebook Inc. co-founder and Harvard dropout Mark Zuckerberg to “Harry Potter” author J.K. Rowling and television host Oprah Winfrey. Last year’s address was given by U.S. civil rights pioneer and U.S. representative John Lewis.

Merkel is the first German leader to give an address at Harvard since 1990, when former Chancellor Helmut Kohl delivered it the year of German reunification.