MINSK, Belarus — The man often described as “Europe’s last dictator” has never looked so shaky.
During his 26 years in power, Aleksandr G. Lukashenko — the iron-fisted president of Belarus and the longest-serving leader in the former Soviet Union — has danced between Russia and the West, alternating praise and blame as he targeted one side or the other as the reason for his country’s and his own misfortunes.
But as he faces his most difficult challenge yet ahead of a presidential election on Sunday, Mr. Lukashenko has lost his political balance, attacking all sides at once as he struggles to explain an upsurge of popular discontent.
After lashing out at Moscow last week over what he described a squad of Russian mercenaries sent to disrupt the election, Mr. Lukashenko on Thursday claimed that Belarus was under attack from a new team of saboteurs who could be Americans, might be Ukrainians or perhaps from Russia.
“A hybrid war is going on against Belarus, and we should expect dirty tricks from any side,” he told security officials in Minsk, the Belarusian capital. “We don’t even know who they are: Americans with NATO, or someone from Ukraine, or our eastern brothers showing their affection toward us this way.”
The outcome of Sunday’s election is in little doubt: Mr. Lukashenko, 65, will be declared the winner for a sixth time. But what is usually a tightly choreographed rite of affirmation has been upset by the largest protests in Belarus since the collapse of the Soviet Union nearly 30 years ago.
In the past, Mr. Lukashenko, who commands a large and often brutal security apparatus, has never been shy about demonstrating that he can crush any dissent. But this time he seems cornered, with opposition rallies in Minsk and smaller cities attracting up to tens of thousands of people.
On Thursday, thousands came out to the Kyiv public garden in Minsk to support Svetlana G. Tikhanovskaya, a candidate whose platform has consisted of one point: Get rid of Mr. Lukashenko. People waved, clapped and shouted of the president, “Go away!”
“People just lost patience,” said Nikita, 27, who declined to give his last name, citing fear of repercussions at his work, a state-run operation.
Ms. Tikhanovskaya’s emergence as a candidate was the result of efforts by Mr. Lukashenko to clear the ballot of all strong competitors. She was declared the united opposition candidate last month after the arrest of her husband, Sergei, who had been a leading opposition contender after attracting a sizable following largely through a YouTube show in which he interviewed people in Belarus’s provinces.
Another would-be rival, Viktor D. Babariko, the former head of a Russian-owned bank in Belarus, was also jailed on suspicions of financial wrongdoing. And the third most popular candidate, Valery V. Tsepkalo, fled the country last month, saying that he was about to be detained.
The president’s mounting troubles, said Aleksandr I. Feduta, his disenchanted former campaign manager, have left Mr. Lukashenko in a situation he has never before experienced: almost entirely bereft of allies outside the security system.
“It is a catastrophe for him,” Mr. Feduta said. “He can extend his rule, but he cannot restore his power.”
The Belarusian economy is faltering in part because of a collapse in oil prices. Members of the economic and government elite have turned against Mr. Lukashenko. Tightly controlled media outlets like state television have lost their grip in the face of vibrant online ones that often support his opponents. And his response to the coronavirus pandemic has also left him exposed.
For months, he denied that the virus was a serious threat and ridiculed that idea that it could be fatal, suggesting that people drink vodka, ride tractors and frequent a sauna to prevent infection.
At the end of last month, he claimed that he had himself been infected but suffered no damage to his health. In an interview on Wednesday, he hinted that he had been deliberately infected, but didn’t specify who would plot against him.
Mr. Lukashenko is now widely regarded as weak, Mr. Feduta said, including by the president’s own officials and members of law enforcement. “The main thing, though, is that Russia sees his weakness, too — the country that sponsored his regime.”
Although the two countries are longtime allies supposedly committed to forming a “union state,” Russia and Belarus have been engaged in a simmering feud for years as the Kremlin has shown increasing reluctance to bankroll its smaller neighbor through reduced-price energy.
Mr. Lukashenko, in turn, has rejected pressure from President Vladimir V. Putin of Russia to surrender some of his country’s sovereignty in exchange for financial help. Last year alone, Belarus lost $400 million because of a Russian oil tax system that prevented Minsk from buying oil at lower rates and then selling it on to Europe at market prices.
The souring of the friendship hit a low point last week, when Mr. Lukashenko accused Russia of sending mercenaries to disrupt his re-election. Thirty-three Russians were arrested, though the exact purpose of their trip was unclear. Moscow demanded the release of its citizens, who it said had simply been passing through Belarus on their way to other countries.
Mr. Lukashenko has also come under pressure from inside his own government, where some have begun to turn against him.
Mr. Tsepkalo, his former ambassador to Washington and one of the most popular opposition candidates, who fled to Russia last month, was one of the highest-ranking members of Mr. Lukashenko’s elite to openly abandon him.
“No one in his immediate surrounding feels that he is part of a team, and no one sees Mr. Lukashenko as an ally,” Mr. Tsepkalo, 55, said in an interview in Moscow. “He finds himself alone now.”
Mr. Tsepkalo, who said that many members of Mr. Lukashenko’s inner circle secretly opposed the president, said that some of them had warned the former ambassador about his imminent arrest, allowing him to flee to Moscow.
Insiders have also leaked information on social media. Stepan A. Svetlov, the 22-year-old founder of NEXTA — the country’s most popular channel on the Telegram messaging app, with 500,000 readers — said he had received a lot of incriminating information about Mr. Lukashenko from government officials.
“People trust us because we cannot be pressured by the government,” Mr. Svetlov, who lives in Warsaw, said in an interview. “They leak us information because they know that we are not in Belarus, where more than half of all bloggers have been arrested recently.”
Yet despite the rising pressure, Mr. Lukashenko controls the electoral system, which can produce any result he needs.
Before the vote, he also visited a number of military bases and anti-riot troops. The fence around his residence in Minsk has been reinforced with metal shields. And army reservists have been asked to return to military service.
“In this situation, he will turn more to people in uniforms,” said Artyom Shraibman, the founder of Sense-Analytics, a Minsk consulting firm and research group, said in an interview.
That could be enough for the president to claim yet another election victory on Sunday. But Mr. Shraibman said Mr. Lukashenko’s era was ending.
“This is clearly the fall season for him,” Mr. Shraibman said. “The question is what month it is — October or November?”