Serbian President Aleksandar Vučić spent an hour on the phone with Vladimir Putin. Officially - about energy, the Petroleum Industry of Serbia (NIS) and the war in Ukraine. Unofficially, it was a farewell call: Vučić confirmed that he told the Russian president he would resign on Sunday, September 27, at around 8 pm.

The main topic was gas. The annex to the Russian gas contract expires on September 30, and after the call Vučić said he was confident the arrangement would be extended "as early as Monday," at an unchanged price. He gave the numbers himself: Serbia pays about 318 euros per 1,000 cubic meters, while the market price is currently 868 euros. In other words - less than half.

That's the currency Belgrade pays for its famous "balance" between East and West. Vučić recently discussed the new arrangement with Russian Foreign Minister Sergei Lavrov in New York too, when he announced there would be a new deal by the end of September. Now he's announcing it on Instagram, in a video message.

The harder topic was NIS. "We also talked about the Petroleum Industry of Serbia, where the problem is more complex, but we exchanged views," Vučić said. Translated from diplomatic into plain language: there's still no solution. All that's left is hope for an outcome "that is good for both sides."

The conversation also touched on Russian Railways' involvement in projects in Serbia, and Vučić thanked Putin for help in fighting the wildfires - the Russian Ilyushin plane and its crew, as he put it, "did a great job."

Then came the sentence that sounds like a message to his successor: "I hope that future presidents of Serbia will also know how to responsibly conduct our country's foreign policy and maintain balance toward all actors on the international stage." Vučić, by his own account, has been in contact with Putin for more than 14 years, and he leaves with thanks to the Russian Federation for its cooperation over that period.

Whoever comes after him inherits gas at a price that depends on a single phone line to Moscow. Is that balance or dependence? And who will be able to hold that balance without the man who built it over years - call by call?