President Trump’s first overseas trip has cast doubt on some longstanding consensus features of U.S. foreign policy—most notably our previously ironclad commitment to the North Atlantic Treaty Organization (NATO). (For commentary to that effect, see here and here.) Is there anything Congress could do to reassert historic U.S. commitments?

The short answer is yes. Although Presidents have very broad authority over foreign affairs, Congress has important powers too. It might consider using them.

What authority does the President hold over foreign policy? The constitutional text is perhaps less clear than we might have liked on this question, and there are a range of scholarly views. The great scholar Edward Corwin famously described the Constitution’s foreign affairs provisions as “an invitation to struggle for the privilege of directing American foreign policy.” Whether or not that is true, it is certainly the case that Presidents over 200 years have successfully claimed the lion’s share of foreign affairs authority.

In particular, presidents across administrations (see here, here, and here) have repeatedly asserted exclusive authority over actual conduct of diplomacy—what official positions the United States takes in communication with foreign sovereigns. (Incidentally, one functional justification for this view is that the executive branch holds superior capacity for nuanced communication, secrecy, expert judgment, and far-sighted calculation of national interests. I’ll let that sink in.)

President Trump’s trip illustrates the power of this authority over diplomatic communication. What the President or his representatives say in diplomatic communications can matter a great deal in foreign relations.

For instance, just consider the impact of Trump’s speech to NATO leaders last week. The heart of the NATO treaty is the Article V commitment by each member state to treat attacks on the others as equivalent to an attack on itself. In his speech, however, the President complained (inaccurately) about other member states’ supposedly deficient defense expenditures while pointedly failing to reiterate the United States’s commitment to Article V—as every other President since Truman had done.

I’ll leave it to foreign policy experts to parse the implications of this position, but it seems likely that the words themselves may have long-lasting effects on our foreign relations and national security. As David Frum has observed, when a possibility like the United States failing to defend a NATO ally goes from zero to not-zero, it may be difficult ever to go back—and the consequences of that shift are difficult to calculate.

So are there any steps Congress could take to mitigate the harm? Yes, because Congress retains important powers too. As the Supreme Court emphasized in a recent decision, “[i]t is not for the President alone to determine the whole content of the Nation's foreign policy.” Among other things, Congress can declare war and regulate foreign commerce; the Senate must approve treaties and ambassadors; and “[u]nder basic separation-of-powers principles, it is for the Congress to enact the laws, including ‘all Laws which shall be necessary and proper for carrying into Execution’ the powers of the Federal Government.”

Perhaps most importantly, as I keep emphasizing (see here and here), Congress has power over appropriations. Even apart from the considerable authority that power provides in its own right, the President’s dependence on annual appropriations gives Congress leverage to assert its priorities on a reluctant President.

So what might Congress do? One simple step would be to pass a concurrent resolution declaring the “sense of Congress” that the United States remains committed to its NATO allies. The resolution could even note Congress’s intention to use its own authorities, including the power to declare war, to make good on our treaty obligations.

A concurrent resolution is not legislation, so it would not need to be signed by the President. Of course, it also would not bind him, but it could nonetheless concretely reiterate the U.S. commitment. (That said, a failed vote on such a resolution, or even a vote by a close margin, could only compound the European jitters Trump has prompted.)

More concretely, Congress might use the coming round of appropriations this fall to mandate particular forms of support and assistance for NATO countries. As I explain in a forthcoming article, Congress could even mandate continued troop levels in Europe. Doing so could provide a concrete statement of U.S. commitment while also ensuring that our forces remain on the ground as a deterrent to any aggression. Congress has sometimes imposed ceilings on such force levels; it may need to impose floors as well.

Even more clearly, Congress could prohibit or restrict further arms sales or military assistance to other countries, such as Saudi Arabia and other Gulf autocracies with whom the President seemed so unnervingly comfortable on this same trip.

I’m not holding my breath for Congress to take meaningful steps to restrain the President. But don’t let it be said that there was nothing they could do. If foreign policy commitments that have served us well for nearly seventy years continue to erode, it won’t be only President Trump’s fault.

Tags: