As President Erdogan of Turkey increasingly threatens neighbors — including a fellow member of the North Atlantic Treaty Organization, Greece, and a partner of the alliance, Israel — can America do more to rein in its wayward ally?

President Biden’s reluctance to criticize Mr. Erdogan’s latest outbursts might owe to Ankara having played a mediating role in a deal that concluded Thursday, when several Americans being held hostage by Russia, including the Wall Street Journal’s Evan Gershkovich, were released to Turkey on the way home to America.

Following threats that “one night” Turkey might seize Greek islands in the Aegean Sea, Mr. Erdogan this week said Turkey could invade Israel. On Thursday, Reuters also reported that since October 7 Turkey has blocked all cooperation between NATO and the Jewish state, a partner of the alliance. 

Several senators have condemned Mr. Erdogan’s threats. The Biden administration, though, has been reluctant to join them. Ankara’s mediation with Russia while the Turkish leader threatens allies is part of a pattern that makes Ankara such a problematic ally. 

“It’s a perfect dumpster fire,” a Turkey watcher at the Foundation for the Defense of Democracies, Sinan Ciddi, tells the Sun. “Erdogan can put a hold on NATO whenever he wants.” Yet, he adds, Washington has tools to lean on Ankara, including by conditioning any new arms sale on ending threats to Israel and Greece.

The Pentagon, meanwhile, is reportedly making contingency plans for the “nuclear option,” Mr. Ciddi says: redeploying America’s largest airbase in the region to a neighboring country from Turkey’s Incirlik. 

Perhaps unconcerned about such drastic moves, Mr. Erdogan seems to increasingly deflect political pressures at home by lashing out at neighbors. His latest anti-Greek statements were made on July 20, which marked the 50th anniversary of Turkey’s 1974 invasion of Cyprus.

Since gaining power in 2003, Mr. Erdogan has coddled Israel’s enemies, including Hamas and other terrorist organizations. He is less enamored with President Abbas, the American-backed leader of the Palestinian Authority. Since October Mr. Erdogan has declined to grant Mr. Abbas’s request to address the Turkish parliament. 

In 2020, Turkey granted citizenship to the Hamas political chief who was killed at Tehran Wednesday morning. “May God have mercy on my brother Ismail Haniyeh, fallen in martyrdom after this odious attack,” Mr. Erdogan said in a statement, denouncing the strike as “Zionist barbarity.” 

Earlier, Mr. Erdogan’s rhetoric was even more aggressive: “We must be very strong so that Israel can’t do these things to Palestine. Just as we entered Karabakh, just as we entered Libya, we might do the same to them,” he told followers at his hometown of Rize on Sunday.

Democrats and Republicans in the Senate were livid. “I’m concerned about any autocratic anti-Israel rhetoric, most especially by the leader of a country that is a NATO ally,” Senator Blumenthal said in a statement. Even Senator Van Hollen, a frequent critic of Israel, was upset, calling Mr. Erdogan’s threat of invasion “outrageous and totally unacceptable.”

At Jerusalem, the foreign minister, Israel Katz, instructed Israeli diplomats to urge NATO members to demand Turkey’s “expulsion from the regional alliance.” Even if the White House was induced to do that, though, NATO has no mechanism to expel any of its members.

The alliance’s decisions are made by consensus, a fact that is increasingly abused by Turkey. Most recently, Ankara held up Sweden’s request to join the alliance until Mr. Biden removed a hold on a $23 billion sale of F-16 fighter jets to Turkey. America had blocked the deal after Turkey had purchased Russian-made S-300 missile defense batteries.

Once Turkey removed its opposition to Sweden, America approved the F-16 sale, on the condition that Mr. Erdogan would not use the weapons against a NATO member, Greece. The caveat followed two years of threats that “one night” Turkey could seize Greek isles in the Aegean.

Athens last week reminded Mr. Erdogan that Greece has F-35 advanced jets, which Turkey lacks. “With F-35s, we can go to Turkey one night,” Prime Minister Mitsotakis said, riffing on Mr. Erodgan’s theme. “One night, you will suddenly find them in Ankara.”

Mr. Erdogan’s recent extra-aggressive tone might be influenced by the political rise of the Islamist New Welfare Party, which is accusing Ankara of being too soft on Israel. The party is led by Fatih Erbakan, whose father, Nejmet, was the founder of the current president’s Justice and Development Party, or AKP. 

Mr. Erdogan is now mostly interested in a new deal with America to co-produce F-16 jets, which would allow him more freedom from American pressure. America could tell him that for such a deal to even be considered, “We need some guarantee that you won’t screw with Israel,” the FDD’s Mr. Ciddi says.