Once the spearhead of the Ottoman Empire, Turkey has again risen to prominence — but for all the wrong reasons. Turkey has prevailed as NATO’s worst ally, disrespecting its core tenets as well as its members’ security interests. It has championed terrorism and has ethnically cleansed the Kurds, forcefully displacing 300,000 in northern Syria and purging 24 Kurdish mayors from office in Turkey. Turkey’s utter disregard for NATO’s purposes — including collective defense and, arguably, promotion of regional stability — and its terrorism warrant a “cold Turkey” expulsion from NATO.

While the North Atlantic Treaty does not stipulate whether expulsion is an available remedy, it is likely so. This is because Article 60(b) of the Vienna Convention on the Law of Treaties — which governs the interpretation of international treaties — notes that material breaches of a treaty, which can justify grounds for a member’s expulsion, include “the violation of a provision essential to the accomplishment of the object or purpose of the treaty.” According to Just Security, violating NATO’s underlying principles, but more so its “object and purpose,” can amount to a material breach that can legitimate Turkey’s expulsion.

Turkey deserves expulsion for challenging NATO’s principles, but also for its failures as a purported geopolitical “ally.” In 1974, Turkey violated arguably NATO’s foremost object and tenet — Article V, a collective defense provision maintaining that an attack on any NATO member is an attack on all — by attacking Greece, then a NATO member, over control for Cyprus. Turkey still occupies Cyprus’s north and is the only country to recognize “the self-proclaimed Turkish Republic of Northern Cyprus as legitimate.” This invasion alone, which displaced 200,000 Cypriot-Greeks, can be invoked to initiate Turkey’s expulsion. Turkey has also defied NATO’s founding purposes, to counter de facto Russian aggression and expansion, by recently procuring a Russian air defense system. Thus, Turkey has demonstrated a dual allegiance to NATO’s historic competitor. Turkey has also undermined regional stability, deploying ISIS and Hayat Tahrir al Sham to fight in Libya, and has refused to aid NATO allies in times of need, denying the U.S. use of the Incirlik Airbase during the Iraq War. A failed NATO ally, Turkey has initiated internal war, has sided with NATO’s historic adversary, and has slighted its allies during key operations.

Turkey’s sponsorship of terror is also overwhelming. In part, this is because Turkey’s prime minister, Recep Tayyip Erdogan, has long championed jihadists and fundamentalists like Galbuddin Hekmatyar. An “Afghani jihad leader,” “Specifically Designated Global Terrorist,” and “Al Qaeda ally,” Hekmatyar offered bin Laden shelter in Afghanistan, and “pledged allegiance to the spiritual leader of the Taliban” to attack American troops. Yet, a young Erdogan can be found sitting beside Hekmatyar’s feet. Erdogan was also a “pupil” of Necmettin Erbakan, the founder of Turkish Islamism and Turkey’s former prime minister. Erbakan founded Turkish affiliates of the Muslim Brotherhood, such as the Welfare Party, and has praised Hamas.

Not surprisingly, Erdogan has advanced his masters’ fundamentalism — harboring, exporting, and financing terror. Turkish authorities allow Hamas to coordinate attacks from Istanbul, while also allowing Hamas officials to “freely” enter “without fear of arrest.” Shortly after hosting Ismail Haniyeh, Hamas’s leader, Erdogan saluted Hamas: “We will keep on supporting our brothers in Palestine.” In fact, ties between Hamas and Erdogan’s Turkey are so strong that “Turkish intelligence agents also maintain close contact with [Hamas] operatives.”

Erdogan has also provided safe haven and funding to members of the Muslim Brotherhood, from which Hamas emerged. Under Erdogan and his AKP, a Brotherhood-linked political party, Turkey has become the “biggest Muslim Brotherhood backer in the world,” even outpacing Qatar, and has “been handed … a leading position in the [Brotherhood] movement, due to [its]success.” Having provided a safe haven for dozens of Brotherhood figures, Erdogan has sheltered “some the movement’s most powerful and influential figures.”

Turkey also safeguards and deploys ISIS fighters. According to the head of Iraqi military intelligence, Lt.-Gen. Saad al-Allaq, Turkey currently harbors “nine [of ISIS’s] alleged terror leaders” and “top financiers.” It has become home to ISIS recruitment cells, and is a refuge to which many ISIS members fled after losing territory. In Turkey, ISIS has planned prison breaks and attacks. ISIS procurement agents and ISIS-affiliated companies also operate from Turkey, and Abu Bakr al Baghdadi was found just miles from its eastern border — suggesting that Turkish intelligence likely condoned nearby ISIS activity.

Most shocking, however, has been Turkey’s direct deployment of troops from ISIS and Hayat Tahrir Al Sham, a Salafi-jihadist group whose predecessor was Jabhat Al Nusra (an Al Qaeda affiliate), in the Libyan Civil War. Reinforcing Libya’s Government of National Accord, which Qatar — one of the world’s largest sponsors of terror — also backs, Turkey’s military has also accepted a military escort from Hayat Tahrir al Sham in Syria. Hence, Turkey not only embraces terrorism, but exports it as well.

Turkey’s ties to terror also involve financing, including “indiscriminate funding” to “al-Q[ae]da based groups in the region, specifically those in the Syrian Civil War.” Turkey remains the only NATO country to be gray-listed by the Financial Action Task Force (FATF), an intergovernmental body committed to “combating money laundering, terrorist financing and other related threats to the integrity of the international financial system.” Funding, exporting, and harboring terror amongst many groups, Turkey champions terror and warrants long-overdue sanctions.

Through violating its duties as a NATO member, and through its strong affiliations to terrorist groups — Hamas, ISIS, Hayat Tahrir al Sham, and arguably, the Muslim Brotherhood — Turkey emerges as candidate for the worst NATO ally in the history of the alliance. Having legal grounds to expel Turkey expulsion, NATO must now do so — and it must do so swiftly in order to protect its integrity.

Jordan Cope is currently a law student at the University of Texas at Austin, where he also completed his undergraduate degree. Having graduated with a B.A. in international relations, Jordan also minored in Middle Eastern studies and can speak Arabic and Hebrew. He has also published research on the security implications of Palestinian foreign aid. He can be followed @JordanCope12.