The United States—through presidential aggrandizement, as well as congressional delegation and acquiescence—has given the president discretion to use force in ways that can easily lead to a massive war.

The Soleimani strike was likely within the president’s domestic legal authority to pursue. But in certain ways, it may push that authority’s limits.

The spending bill authorizes the Pentagon to create procurement pathways in which software can be purchased in less than a year. If effectively implemented, the change would be dramatic.

In Iraq, the Trump administration’s military response to a fatal attack on U.S. personnel has triggered a new political crisis. The U.S.-Iraq relationship may not escape unscathed.

The Millard Fillmore administration’s diplomatic machinations toward Hawaii are a curious example of the executive branch regarding itself as constitutionally empowered to threaten war but constrained fr...