Khalil Ashawi / Reuters

After President Donald Trump’s disastrous decision to abandon the Kurds and withdraw our troops from northern Syria, Congress spent this past week trying to decide how best to respond. A resolution of denunciation? Tough sanctions on Turkey? Reconsider our relationship with Turkey? Convene the coalition against ISIS and consider how to recapture or even track the hundreds of escaped fighters?

I think we have an even bigger problem on our hands.

Until now, it was reasonable to debate whether Trump was simply an unconventional president, the first with no prior experience serving in either our military or government, or whether he was truly willing to work with foreign dictators to place his own political interests ahead of our nation’s. This week, we learned that this was a false choice—he’s both.

First, despite the temporary cease-fire that Vice President Mike Pence and Turkish President Recep Tayyip Erdoğan announced on Thursday, the damage President Trump has caused cannot be undone. He betrayed our Kurdish allies, aided Russia and Iran, and gave ISIS a chance to reconstitute itself—all to serve his own perceived political interests.

Second, Trump’s abrupt order to withdraw U.S. troops from northern Syria was not a legitimate response to Americans who are tired of “forever wars.” An abrupt withdrawal from Syria that emboldened our enemies and has already led to the death of hundreds of innocent people was not what the American public had in mind. And just days after Trump announced the withdrawal from Syria, abandoning the Kurds and risking the revival of ISIS, he deployed another 3,000 troops to Saudi Arabia. The net impact is more American troops in the Middle East.

Less than a year later, all it took to convince Trump once again that Mattis and nearly every serious foreign-policy and security leader from either party in Congress were wrong was a phone call with Erdoğan, the increasingly authoritarian leader of Turkey.

The president apparently chose to listen to the Turkish dictator instead of his top advisers and the bipartisan consensus in Congress because he thought it would make a good campaign talking point.

While we need to do everything we can to limit the impacts of the president’s decision, members of Congress also need to ask ourselves what we can do to prevent Trump from letting other dictators steer U.S. foreign policy as Erdoğan has done.

What’s to stop Trump from pulling the United States out of the North Atlantic Treaty Organization, offering up Taiwan to China’s President Xi, or handing over Estonia to Vladimir Putin? What about withdrawing our troops from South Korea to secure a nuclear deal with Kim Jong Un or abandoning the Baltics to secure peace in Ukraine? Those terrible ideas might strike Trump as bold strokes designed to bring our troops home, too.

We can’t let any of those hypothetical situations come to fruition, because, as we have seen in Syria, the vacuum of American leadership is quickly filled by adversaries.

If the Senate fails to act now to constrain the president and dissuade foreign dictators from asking Trump to desert longtime allies, disregard U.S. interests, and overturn years of U.S. foreign policy, we will have no one to blame but ourselves. It’s true that foreign policy is primarily driven by the executive branch, but it’s Congress’s role to establish guardrails, particularly when the president cannot be trusted to pursue American interests.

The Senate needs to put Trump, our national-security leadership, our allies, and the strongmen with whom Trump regularly flirts on notice. We need to demonstrate to dictators that our system is different: Congress can constrain the president and punish dictators for acting against our interests. There is broad bipartisan support for doing so in this case, and that should extend to preventing a repeat performance.

The Senate must preemptively put in place mechanisms to defend our democracy and our network of alliances before Trump acts against our interests once again, whether to indulge his isolationist impulses or to distract from impeachment.

Specifically, we should pass legislation to prevent a U.S. withdrawal from NATO without congressional approval, require Senate approval of any adjustments to U.S. troop levels in South Korea or Japan, and debate an Authorization for Use of Military Force that accurately reflects the conflicts in which we are currently engaged and claws back war-making authority from the executive branch.

Trump’s tragic decision in Syria unleashed ISIS and abandoned our Kurdish partners to the mercy of their new defenders, whether “Russia, China, or Napoleon Bonaparte,” as Trump tweeted. This cannot be accepted on its own, and it cannot be allowed to establish a new precedent for American foreign policy.

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