"Congress is the institution vested with the power to declare wars, to debate where we send troops, and decide which conflicts are funded."

David Harsanyi writes in the Federalist,

...Congress is the institution vested with the power to declare wars, to debate where we send troops, and decide which conflicts are funded. Presidents have been ignoring this arrangement, abuse authorizations for the use of military force (AUMFs), and imbue themselves with the power to engage in conflicts wherever they like, without any coherent endgame, and without any buy-in from Congress.

...It’s a bipartisan problem. Barack Obama, whose political star rose due to his opposition to the Iraq war, was perhaps our worst offender, circumventing Congress and relying on a decade-old AUMF, which he invoked 19 times during his presidency, to justify a half-hearted intervention against ISIS (not al-Qaeda) in Syria (not Afghanistan.)

..It was also Obama who joined Europeans in the failed intervention in Libya, where he worked under NATO goals rather than the United States law. There was hardly a peep from Democrats fretting over the corrosion of the Constitution.

...The only thing we can be certain of is that there few good options in the Syria mess, and that includes our allies. Although the Kurds have endured much as a people, and deserve our support, the Kurdish PKK, our allies in northern Syria, aren’t chaste freedom fighters but Maoists with ties to terrorist organizations.

Or, in other words, we face few good options mired in perhaps the most volatile situation in the world. Under these conditions, our foreign policy shouldn’t be driven by the arbitrary “great and unmatched wisdom” of any single person. This brand of unilateral power was problematic when the well-mannered Obama sold out Syria to coddle the Iranian terror state, and it’s problematic when an impulsive Trump acquiesces to the wishes of Erdogan. (Although Washington only seems to freak out when the word “withdrawal” is mentioned.)

Read more here.