Congress Must Fight Back Against American Isolationism

For years, America’s biggest advantage in our strategic competition with China has been our global network of strong alliances. Unfortunately, President Donald Trump’s erratic behavior has endangered that. 

Over the last two weeks, several of our oldest, closest allies have taken steps to hedge their bets and distance themselves from the United States. The result: America is becoming more isolated in a dangerous world. 

Republicans in Congress need to wake up to this danger and stand up for America’s alliances before things get worse. When faced with President Trump’s outbursts, my Republican colleagues often tell me to pay attention not to what he says, but to what he does. I’d give them the same advice with respect to our allies. 

In the last few weeks, Canadian Prime Minister Mark Carney has gone to Beijing and signed a new trade deal with China. UK Prime Minister Keir Starmer has also laid the groundwork for deeper cooperation with Beijing, despite a myriad of security concerns. French President Emmanuel Macron went to the World Economic Forum and solicited additional foreign direct investment from China. And after nearly two decades of negotiations, the European Union finally closed a massive new trade deal with India and a bloc of South American countries to reduce its reliance on the United States. 

Any one of these would be concerning. Taken together within the span of two weeks, it’s a five-alarm fire for our place in the world. These nations aren’t just our closest allies—they’re the bulwarks of the international order that have made the United States the strongest and most prosperous nation on earth. 

Now, our allies no longer trust Trump, and by extension, the United States. 

This was apparent when I led a bipartisan congressional delegation to Copenhagen two weeks ago, at the height of Trump’s threats against Greenland and Denmark. In every conversation I had—with business leaders, with Greenlandic and Danish officials, with Danes on the street—I heard anger and alarm, but more than that, I heard the risk of a fundamental break. As NATO members, they would gladly come to our defense, as they did after the September 11 attacks. More Danes fought and died alongside us in Afghanistan on a per capita basis than any other ally. Sadly, they no longer trust that we’d come to their aid in turn. 

I’ve witnessed that same break in meetings with world leaders on every continent over this past year. They’re alarmed by the President’s unhinged behavior, and especially his harmful, unpredictable tariffs. 

In April 2025, I visited Taiwan and saw proof of this damage—and of Trump’s dangerous foreign policy approach. Taiwan had just pledged massive investments in the United States to the tune of more than $100 billion. Soon after making that pledge, Trump announced his intention to impose a 32% tariff rate anyway. The United States has long requested that Europe contribute more to NATO. Last year, they came forward with substantial new investments in our collective defense, but that wasn’t enough for Trump. Now, our allies are increasingly wondering: What is the value of investing in the United States if they turn on us the next day? 

The executive branch is driving our hard-won partners and allies away. It’s the duty of the legislative branch to put a stop to it. 

First, Congress should step up and end Trump’s regime of tariff-by-tweet. Our European partners were rightly alarmed by the president’s threats of significant new tariffs on NATO allies if they did not support his bid to seize Greenland. It even led the Europeans to consider using their “trade bazooka”—a tool designed to counter China—against Washington instead of Beijing. The Senate has passed several bipartisan resolutions to constrain the president’s use of tariffs on our closest partners. It’s time for the House to do the same. 

We must also enact my STABLE Trade Policy Act, which would prohibit any new tariffs on close allies and trading partners without congressional approval. That’s how we send a clear message to the world that Congress won’t stand for this.

Secondly, we should pass the War Powers Resolutions to prove that Trump is not the sole driver of American foreign policy. By bypassing Congress, Trump has repeatedly demonstrated that he views his constitutional duty to consult with Congress as an inconvenience, at best. And given the president’s preference for “shock and awe” military operations, Congress cannot wait to stand up.

Along the same lines, we should pass Senators Shaheen and Murkowski’s bill, which would prevent the United States from invading NATO allies without a green light from Congress, similar to then-Senator Rubio and Senator Kaine’s 2023 bill prohibiting the United States from leaving NATO without congressional approval. President Trump may have backed off his threats to invade Greenland, but only a fool would say he might not wake up tomorrow and change his mind.