Turkey, both as a country and as a long-term NATO ally of the United States, is becoming a more complex problem.

The European Parliament voted Nov. 24 to suspend accession negotiations with Turkey. These have been ongoing for 29 years, but have been kept from completion — and Turkish membership in the European Union — by the hurdles the E.U. has in place for Turkey to cross. The E.U. needs Turkish labor, and also could be well-served by Turkey as an E.U. member as a bridge between it and Muslim countries to the east in Asia. At the same time, there is resistance among some E.U. members to the idea of a large, predominantly Muslim state being added to the E.U., comprised largely of states that consider themselves Christian.

Primary objection to Turkish membership — and the proximate cause of the E.U. parliamentary vote — now centers on some of the steps that the government of Turkish president Recep Tayyip Erdogan has taken in the wake of the attempted Turkish military coup d’etat directed against his government in July. There have been many arrests, of military officers, journalists, academics, and others of Mr. Erdogan’s opponents, and some of those arrested have been charged in court.

The problem for the rest of Europe, apart from giving up the advantages of Turkish E.U. membership, is that there is still in place a deal under which Turkey takes various actions to restrain the flow of migrants from the wars of the east — in Afghanistan, Iraq, Syria, and Yemen — into Europe, in return for concessions that Europe made to Turkey. Mr. Erdogan has now said that if the E.U. does not continue the negotiations, he is going to open the floodgates and let the migrant flow resume. That would be a disastrous development for Western Europe.

In addition, finding Western Europe increasingly hostile, Mr. Erdogan has been cozying up to Russia, headed by the West’s current favorite villain, Vladimir Putin, thus reversing alliances that have been in place since the end of World War II. Turkish reorientation also has large implications for the wars in Iraq and Syria. America has a dog in those fights, as does Turkey, on the opposite side.

All in all, fixing relations with Mr. Erdogan’s Turkey will be, for Europe and for U.S. President-elect Donald Trump, an ongoing and multifaceted problem.

First Published December 3, 2016, 5:00 a.m.