Seen as a notch in President Baiden’s diplomatic belt, Turkey’s abrupt agreement to allow Sweden to join NATO may well be far from the last word on America’s relations with a “challenging ally.” 

Meeting Mr. Biden at Vilnius Tuesday, President Erdogan was basking in the glory of what the Turkish press saw as a real victory for the strongman. Beaming as Mr. Biden praised his “leadership,” the Turkish strongman stopped just short of making an endorsement in America’s 2024 election.

“My dear friend,” Mr. Erdogan said, “I would like to first of all thank you for congratulating me in the aftermath of my re-election to my current post,” and “I would like to take this opportunity to wish you the best of luck” in the upcoming election. “I look forward to being with you in the next five years,” Mr. Biden shot back. 

How long can this Turkish honeymoon last?

For months Mr. Erdogan used the fact that all NATO members must approve new members to block Sweden’s accession. After receiving some concessions from America and Sweden, he removed his opposition. Will his extortionist tactics bode ill for NATO? 

“NATO’s expansion is a win, but what about existing members who can now leverage their position to get things, because they’ve now seen how successful it could be?” a Turkey watcher at the Foundation for Defense of Democracies, Sinan Ciddi, asks the Sun.   

In the space of less than 24 hours this week, the famously volatile Mr. Erdogan has done a complete 180, at first adding a new hurdle and then removing all obstacles to Sweden’s accession to NATO.

On Monday morning the Turkish strongman surprised everyone at Vilnius by demanding that Turkey be admitted to the European Union before Sweden is admitted to NATO. By nightfall, NATO’s secretary-general, Jens Stoltenberg, tweeted that Turkey had ended its objection and agreed to let in Sweden.

“President Biden and his team worked hard to get Erdogan to ‘yes’ and are to be applauded for their efforts,” a Brookings Institution Turkey watcher, Asli Aydintasbas, writes in the Washington Post, noting that Mr. Erdogan’s top wish was approval from Washington for the sale of F-16 fighter jets in order to replenish Turkey’s aging air force.

Mr. Biden is pressuring Congress to approve the sale, and one top opponent, the Senate Foreign Relations Committee chairman, Robert Menendez, is now convinced that it’s good “to keep Turkey inside the NATO tent by going ahead with the sale,” according to Ms. Aydintasbas. 

Sweden made several concessions to Turkey as well. Last week a Kurdish man was convicted of financing the Kurdish Workers’ Party, or PKK. It is outlawed in Turkey and is listed by America and the European Union as a terrorist organization. Yet, many PKK members have long found shelter in Sweden.

Stockholm is now considering banning PKK rallies, and has signed an agreement with Ankara to cooperate in the fight against terrorism.

A recent Swedish court authorization for burning a Koran in front of a Stockholm mosque has raised Turkey’s ire. Now, Prime Minister Kristersson says that even though Sweden’s constitution guarantees freedom of speech, “everything that’s legal is not appropriate.”

By acting tough with NATO, Mr. Erdogan clearly managed to change some minds in Europe and in America.   

During a Senate hearing in March, Mr. Menendez read out a list of Mr. Erdogan’s misdeeds, including Ankara’s 2017 purchase of a Russian S-400 air defense system, which led to Congress putting a hold on selling F-16s to Turkey. “What would you call such a country?” Mr. Menendez asked Secretary Blinken. 

“I think I would call that a challenging ally,” Mr. Blinken answered. “I call that country Turkey,” Mr. Menendez protested, adding he did not believe such a country “deserves to have F-16s sold to it.” 

Yet, will Congress now turn around and remove its opposition? Meanwhile, the Turkish parliament must now ratify Mr. Erdogan’s approval of NATO’s expansion — and that may require additional concessions to Ankara. 

As Mr. Ciddi notes, the Turkish economy is in real trouble. While it may currently enjoy a short-term reprieve as the tourism season is in full swing, the country’s cash crunch may hit a head in the fall. Financial help from America or Europe may be necessary to shore up Mr. Erdogan’s hold on power. 

Following signs of weakness at Moscow, where a short-lived coup threatened President Putin, Mr. Erdogan may have decided to bet on strengthening his ties with the West. Yet, Russia remains the largest importer of Turkish goods and is Turkey’s top supplier of natural gas. Moscow oligarchs keep assets in Turkish banks, and Mr. Erdogan is yet to join Western sanctions against them. 

Mr. Biden did well by resolving the NATO impasse, but he should beware of sitting on his laurels. As Ankara smiles westward, it refuses to burn its Russian bridges. The alliance with the unreliable Mr. Erdogan will continue to present America with future challenges.