Turkey's decision to strengthen its air defenses has fueled serious tensions with the United States. As part of the decade-long negotiations, the Turks had unsuccessfully attempted to buy Washington's missile defense system due to disagreements over pricing, joint production and technology transfer. Having been turned down by the Americans, Ankara turned to European and Chinese manufacturers. In the end, Russia agreed to Turkey's terms and the two countries shook hands on the S-400 deal.

U.S. officials have been strongly criticizing Turkey's move. Several days ago, the Turks received a letter from the Pentagon informing them that Washington would exclude Turkey from the F-35 fighter jet program if Ankara failed to abort the S-400's delivery. The letter was leaked to the press before it reached its destination. The Turkish response was that "the content and language of the letter was not in line with the spirit of alliance." The Turks are currently writing their response to the U.S. letter.

Yet the U.S. went even further. It threatens to impose an embargo on Turkey in various areas. Having weaponized its economy against China, Washington signals that it could resort to the same method to tame Turkey. The Pentagon's letter is full of such clues.

To back down, the Americans want Turkey to reconsider the S-400 purchase. The Turks respond by saying that the equipment has already been bought and will be delivered next month. What else does the U.S. want? The list of demands is quite long. Washington has effectively aligned its Middle East policy with Israel's priorities. As such, it wants Turkey to stay away from the brewing fight over energy resources in the Eastern Mediterranean, turn a blind eye to terrorist groups in Northern Syria, keep silent about the plan to divide Jerusalem, and join the ranks of a regional anti-Iran bloc. In other words, the problem goes far beyond the S-400 missile defense system. At the heart of Turkey's troubles with the United States is the former's emphasis on its national interest. Washington thus seeks to punish the Turks for protecting their interests and forces Ankara to choose between its vital interests and the Western alliance. Will Turkey backtrack on its commitments?

The fight against terrorism, regional stability, developing defense systems, Jerusalem's status and remaining part of the Western alliance are all vital interests for Turkey. Which one is Ankara supposed to abandon under U.S. pressure?

Turkey's top priority is always Turkey. Washington's partnership with terrorist groups targeting Turkish citizens is an open secret. The U.S. did not demonstrate any intention to terminate that relationship. It does not support Turkey in key regional issues either. Instead of acting as a friend, Washington has consistently behaved like an adversary seeking to incapacitate Turkey. Under those circumstances, it makes no sense to question why the Turkey-U.S. relations are going badly. Having undermined the United Nations, the U.S. now raises questions about NATO's future. U.S. President Donald Trump's remarks on the alliance have weakened confidence in NATO. The Western alliance, too, suffers from Trump's reckless policies. The United States could lose Turkey altogether by mounting pressure on Ankara now. It is important to ask who will dismantle the Western alliance.