(cited by Washington Post)
1945 (with Erik Gartzke)
While the president has a broad power to threaten military action, threats need to be perceived by adversaries as credible in order to achieve a deterrent effect. Given the enormous political exposure a president would be risking by engaging in a major conflict unilaterally, the threat to do so absent congressional support would lack significant credibility in the eyes of potential U.S. opponents. Therefore, in order to minimize the possibility of a war over Taiwan, pursuing a policy of strategic clarity requires that Congress make its own policy position clear and unambiguous as well.
Even if Congress is unable to formally take away the president’s ability to launch a war against Iran, it nevertheless has the capacity to effectively create expectations of retaliation that can deter an otherwise capable president from being willing to use force. It might be true that “one person decides[,]” but Congress is able to heavily shape the strategic environment in which this decision is made. While the president is able to act unilaterally, fear of Congress’s “power to hurt” may prevent the president from being willing to do so.
Since President Truman’s “police action” in the Korean War, scholars in law and political science have considered the possibility that presidents would attempt to substitute congressional authorization with authorization from an international organization when using military force. While presidents have on multiple occasions appeared to do so, after considering the scale of the operations undertaken there is clear evidence that presidents since Truman have avoided major war absent formal congressional approval. Instead, uses of force undertaken with mere international approval have consistently been orders of magnitude smaller in scale than those conducted pursuant to formal authority from the legislature.
A logic of consequences and politics—not any logic of appropriateness, constitutionality or norms—drives the observed lack of serious war absent congressional authorization over time. Thus, even a president with little concern for respecting constitutional norms and willing to supercede the current test put forth by the OLC would nonetheless be compelled de facto to conform with this paradigm or face the political consequences of “going alone.”