Washington — Seventy years ago Monday, Secretary of State George Marshall delivered a Harvard commencement day address that became the framework for what we call the “Marshall Plan” for European recovery.

It’s a cruel anniversary this year, as we watch President Trump dismember the world order that Marshall and his colleagues helped build.

Dean Acheson, one of Marshall’s colleagues and his successor at State, famously titled his memoir “Present at the Creation.” These past few months, many of us have worried if we are now “Present at the Destruction.” Trump’s capricious jabs at allies in Britain, France, Germany and elsewhere are undermining the global alliances and institutions created after World War II on which American power has rested.

Nowhere is this inflection point more striking than in Russia, where I visited last week. If this were a football game, Russians would be spiking the ball in the end zone. My guess is that their euphoria is premature. The only people who will dismantle this order are the ones who built it — Americans and their European allies. Trump is a bulldozer, but he’s unintentionally reawakening the sense of interdependence and idealism that built the “liberal international order.”

One of my favorite George Marshall aphorisms is: “Don’t fight the problem. Decide it.” It’s an admonition to be pragmatic, to identify the obstacle and then overcome it. In the “strange bedfellows” department, I discovered the other day that Trump had tweeted that precise quote on July 10, 2014. (This was one of more than two dozen tweets he sent out that day. Others included blasts at Barack Obama, Rosie O’Donnell, Mexicans and gun-control advocates — plus two plugs for Trump hotels in Hawaii and Panama.)

But let’s not fight the problem. Here are three points about the Marshall Plan that are lessons for today:

l The Marshall Plan reflected a domestic political compact to address a crisis overseas. Without consensus at home, nothing would have been possible abroad. And for all Marshall’s genius, it was President Truman’s political toughness that made it happen.

Gaining support for European recovery wasn’t as easy as it looks in hindsight. Republicans had swept the 1946 congressional elections and won control of the House and Senate. There was lingering concern whether Truman was up to the job. But his weak standing was bolstered by his announcement in January 1947 that Marshall would serve as his secretary of state.

Truman steadied through that spring of 1947, not least because of Marshall, whom he venerated. His presidency stabilized. His will to combat Russian expansion increased. He announced the “Truman Doctrine” in March of 1947 to assist Greece and Turkey.

As he began to take hard, principled stands, Truman found surprisingly broad public support. Collier’s magazine said Truman “hit the popularity jackpot.” The moral for the future is that strong policies create their own constituencies of support.

l Marshall mobilized the tools of government quickly and efficiently, much as he had as Army chief of staff. He had visited Moscow in April 1947 and returned deeply worried. The Russians were prepared to let chaos continue in Europe; there was no real chance for negotiation. (Sound familiar?)

Marshall didn’t fight the problem. He summoned George Kennan on April 29 and asked him to gather a group immediately to recommend policies to save Europe. Kennan delivered his report less than a month later. It had the simplicity of any world-changing idea: U.S. aid “should be directed not to combating Communism as such but to the restoration of the economic health and vigor of European society.”

l Policy enunciation matters less than implementation. The most important fact about the Marshall Plan is that all the instruments of American power were utilized to implement it. This demonstration of American commitment had an immediate effect on European morale.

As my father (who heard the speech in Harvard Yard that day) likes to say, “A thing worth doing is worth overdoing.” But unfortunately, the term “Marshall Plan” has become a buzzword for big, dreamy projects that never get done. If you do a Google search on the phrase “We need a Marshall Plan for … ” you get about 8,000 different entries.

Let me choose one: The screaming fact about the world of 2017 is that we need, yes, a Marshall Plan, for the post-Islamic State Sunni areas of Iraq and Syria. Mosul and Raqqah will likely be cleared in a matter of weeks. The need for governance, security, economic development and rule of law is truly urgent, and bears comparison to Europe’s desperate situation in 1940.

The barriers to good American policy and leadership are not abroad — they’re at home. The biggest obstacle, sadly, sits in the White House.

— David Ignatius is a columnist for Washington Post Writers Group.