The current conflagration with Iran has once again brought to national attention the ability of a president to initiate military actions, with almost no consultation with Congress or other international allies. To some degree this is a feature of the modern presidency, developed in the context of the Cold War, under which presidents can use a large and permanent military apparatus to carry out attacks around the world. At the same time, we can think about President Trump’s actions within the context of presidential history and judge the extent to which he resembles presidents of other eras as well.
Presidents since the nation’s earliest days have always had the ability to use military force. Article II of the Constitution provides for a strong executive, as Hamilton noted in Federalist 70, especially making the President the Commander-in-Chief of the armed forces – whereas under the Articles of Confederation there was no executive at all. The provisions of the Constitution allowing for a national military were similarly strengthened from the Articles, including giving the president the ability to call the state militias into national service. Because of these constitutional arrangements, there are, as Aaron Wildavsky argued many years ago, essentially “two presidencies” – that is to say, there is a much stronger presidency in foreign policy than in domestic policy.
Since the earliest days of the nation presidents have used this enhanced strength on many occasions. It was true against the Barbary Pirates under Jefferson, a conflict he engaged in without explicit congressional authorization, and it was true in battles against Native Americans on dozens of occasions during the early republic.
How might the current conflict resemble earlier ones? Perhaps this might play out a bit like the initiation of the Mexican-American War in 1846. A grievance, in that case the question of Texas’ proper borders, and a provocation that then leads to all-out war (when President Polk sent General Zachary Taylor’s forces into the disputed region between the two nations). Polk clearly wanted the war and had run on a platform of expansion, both in Texas and in Oregon. Or perhaps this is more like the Spanish-American War, when preexisting issues between the two nations were sparked by an event (the explosion aboard the USS Maine) that then led to war. President McKinley was more reluctant to use force up until that point, then he changed his mind, seeing this as a Spanish attack.
President Truman initiated a war in Korea, defending a national interest we had fighting Communist expansion in the context of the Cold War. Truman pushed forward in the conflict even with no authorization from Congress. Since then, presidents have had a largely free hand to initiate war. But there is also scholarly work that shows how sometimes Congress can stop wars from occurring, or can influence the direction of conflict once initiated.
We’re too early here to know how the current events will unfold. But one thing we do know is that presidential power in foreign policy is broad and their ability to bring the nation into a conflict remains a possibility at any moment.