No matter the merits of the case for destroying Isis, the fact remains that it’s unconstitutional for the president to go to war without congressional approval.

The downing of a Russian jet by NATO ally Turkey on its Syrian border two weeks ago may have resulted in the beginning of a significant, comprehensive Russian policy shift toward Turkey, and it is likely that the estrangement between the two countries will continue even if the tension over the jet is eased.

Yesterday the House of Commons voted to extend the zone of British combat operations from Iraq to Syria. The debate--I watched some of it--was prolonged, intense, and mostly respectful. This morning I woke to find the tag #bloodonyourhands trending on facebook and twitter, as opponents of the decision rallied against the Labour MPs who swung the decision.

What are Europeans willing to fight for?