This week, President Obama OK'd airstrikes against Islamic State targets using an unrelated 13-year-old authorization for use of military force as his legal mandate. Seems like a big deal. It may even be a good idea, writes David Harsanyi. Yet even though Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, informed the Senate that ground troops could be needed to finish the job—whatever that job may be—the president didn't bother to ask for permission. And really, why should he? With the midterms approaching, elected officials in Congress have remained vigilantly quiet or tepidly supportive. But if war isn't worth a Congressional vote, what is?