Editors’ Note: The president enjoys his or her greatest power in foreign policy, writes Tom Wright—and a Trump administration would pose the greatest shock to international peace and stability since the 1930s. This post originally appeared in the Financial Times.



The damage a President Trump could do to the American republic is thankfully limited. A president is not a king. There are laws and a court to enforce them. There is Congress to block him. If a president breaks the law, he can be impeached. America may become a more intolerant and chaotic place under Donald Trump, but thanks to its institutions the republic will survive.

The world is a different matter. The president enjoys his or her greatest power in foreign policy. His power to use force is well known. As important, though, is what he can choose not to do. He can unilaterally refuse to defend an ally. He can choose to strike a bargain with Russia instead of deterring it. He can pull out of a trade deal. There are fewer checks and balances. Damage done in one year may never be undone.

A Trump administration would pose the greatest shock to international peace and stability since the 1930s. This is not because Mr. Trump would invade other countries but because he would unilaterally liquidate the liberal international order that presidents have built and defended since Franklin Delano Roosevelt. If the word “isolationist” has any meaning, he qualifies as one.

Mr. Trump has a coherent and consistent worldview that dates back almost 30 years when he spent $95,000 on a full-page advertisement in the New York Times to publish an open letter to the American people on U.S. foreign policy. It was this worldview that he described to the Washington Post editorial board on Monday. It appears in virtually every interview and speech he has given about world affairs since the 1980s.

Simply put, Mr. Trump thinks America’s allies and partners are ripping it off and he wants out of America’s leadership role in the international order. Over and over again, Mr. Trump has questioned why the United States. defends Japan, South Korea, Germany and other nations without being paid for it. Just this week, he promised to significantly diminish U.S. involvement in NATO and when asked if America “gained anything” from having bases in east Asia he replied “personally I don’t think so”. This is not about a more equitable share of the burden, which many have called for. Mr. Trump believes that the U.S. gains little from having allies unless it is paid handsomely paid by them.

He also opposes every trade deal America has signed over the past 30 years. He wants to use tariffs and other protectionist measures to bludgeon other countries into accepting lopsided agreements that disproportionately benefit the United States. He has suggested charging other countries for use of the sea lanes. Under his presidency, the open global economy would slam shut.

As he shuns America’s allies, Mr. Trump would seek to strike deals with Vladimir Putin, president of Russia, and other authoritarian strong men. Mr. Trump has received Mr. Putin’s endorsement and has called for much better relations with Russia.

Meanwhile, to deal with threats to the American homeland, Mr. Trump has promised his own Chechnya-style scorched-earth policy of targeting civilians and using torture.

Some think that Mr. Trump will moderate these positions if he is elected, but it is unlikely that a 70-year old who has held these views for decades and probably views himself as a prophet will abandon them at exactly the moment he feels vindicated and empowered.

The day after his election, allies in Europe and Asia will rightly worry if their security relationship with the United States remains intact. Russia and China will have an unprecedented opportunity to achieve in a single presidential term what they thought would take decades, namely the destruction of the U.S.-led alliance system.

These are the true stakes of the 2016 election. The campaign will be unlike any other as the fundamental pillars of post-second world war American foreign policy are put up for debate. Hillary Clinton, the probable Democrat nominee, might be synonymous with the establishment, but her destiny is clear. It is to explain why an open and liberal international order benefits ordinary Americans. It is to show how the closing of the global economy, the end of alliances and dawning of an authoritarian age poses as great a threat to American interests now as it did in the late 1940s when the architecture of U.S. leadership was created.

The international order can survive many things—terrorist attacks, Russian aggression, Chinese revisionism and an international financial crisis—but the collapse of American leadership may prove a disaster too far.