Serbian President Aleksandar Vucic has confirmed the date once again: on Sunday, 27 September, he resigns as president of Serbia. "On Sunday the 27th I am submitting my resignation," he said on Radio Belgrade. After that, as he announced last week, he joins the campaign for the early parliamentary elections on 25 October - "as an ordinary citizen".

That "ordinary citizen" has an electoral list the Republic Electoral Commission has already registered under the name "Aleksandar Vucic - United Serbia", and since the start of September he has openly said he wants to be the candidate for prime minister. If he gets the backing, he promises "the smallest government in Serbia's history" - a prime minister and no more than 12 ministers. The man who dissolved parliament himself on 9 September and called the elections himself is now stepping down from the presidential chair to fight for the prime minister's. The Balkans recognise this move instantly: one step back to take two forward.

Inside his own party he announced a purge: "I will do everything I can to have at least 50 percent of mayors and municipal heads replaced three months after the government is formed," Vucic said, explaining that those people "did not want to listen to their fellow citizens, they thought more about themselves". He will use the political influence he holds inside the Serbian Progressive Party to make the changes. The question raises itself: who selected and defended those mayors all these years?

He did not spare the Student List either, also officially registered for the elections. Of its lead candidate Ilija Srdanovic he said: "Just listen to the last two interviews by the first name on the Student List and if that is politics, if that is what you want to vote for, go ahead, it has nothing to do with me." In the interview Srdanovic spoke about people loved by their families and communities and mentioned the nickname "the unloved one" - without naming Vucic. The president took it as a message aimed at him. When a nickname with no name attached lands on the head of state, it says more about the atmosphere than any poll.

The resignation comes in a week in which Vucic, with no journalists present, opened a plant assembling Israeli military drones in Belgrade's Makis district - promising around 100 jobs and at least three more such plants. According to a BIRN investigation, the company running the plant appeared in the register under a new name just hours after the opening, and one of its new directors is the Israeli lawyer Zion Amir, who last year represented Prime Minister Benjamin Netanyahu before the Supreme Court. A president on his way out, but military contracts that stay - that is the sequence worth remembering.

And what follows if he actually signs? Under Serbia's constitution his term ends the same day, the speaker of the National Assembly stands in temporarily, and new presidential elections must be held within three months at the latest. Translated: after 25 October Serbia also heads for an early presidential election. Two electoral cycles in a matter of months, in a country where even after the president resigns the biggest name in the campaign stays the same.

Vucic has already changed office once without changing the address of power - from prime minister to president in 2017. Serbia will now find out whether that model works in reverse, and whether the "ordinary citizen" returns after 25 October to a prime minister's chair he never really left.