Russian opposition activist Alexei Navalny speaks during a September interview with the Associated Press in Moscow. On Tuesday he officially announced his bid to run in the 2018 presidential election. (AP Photo/Pavel Golovkin, file) (Pavel Golovkin/AP)

Even in an era of political upsets, this one’s a long shot. 

Alexei Navalny, the opposition politician who helped lead street protests against Russian President Vladimir Putin here in 2011, announced Tuesday that he would run for president of Russia in 2018, sending a rare jolt of electricity through Russia’s subdued opposition. 

“I will take part in elections for the presidency of Russia,” the vocal critic of Putin declared in a video released on the Internet. “Genuine elections are not just the victory of one person. They’re a clash of ideas, competition between programs.”

Navalny’s candidacy, the first declared by any politician, marks the beginning a long election cycle that seems headed for one, inevitable conclusion: a victor anointed by Russian President Vladimir Putin.

There’s a good chance that will be Putin himself.

But the Russian leader, who turned 64 in October, has not said whether he will stand for reelection. He has served as president of Russia for three terms since 2000, a perpetual administration broken only by a stint as prime minister. He has no heir apparent.

Much has changed since Navalny, an anti-corruption activist who used his status as an investor in state companies to expose corruption, emerged as a leader of Russia’s “White Ribbon” protests in 2011.

The demonstrations, mainly in Moscow, united left- and right-wing political activists with ­middle-class and liberal intelli­gentsia in a rare outburst of anger at Putin’s return that year to the presidency. 

Since then, Russia has annexed Crimea, to the delight of Putin’s base; coordination between opposition groups has collapsed; and demonstrators have been targeted in criminal cases, with some receiving years of hard time in Russian prisons. Boris Nemtsov, a former deputy prime minister and one of Putin’s most vocal critics, was gunned down in sight of the Kremlin in 2015.

Navalny’s brother Oleg was sentenced to 3½ years in jail on embezzlement charges in 2014. Alexei also was charged in several prosecutions that he called politically motivated and received a suspended sentence for embezzlement in 2013.

Convicted criminals cannot run for president in Russia. But the conviction was overturned this year after criticism by the European Court on Human Rights. Navalny is facing a ­retrial; a guilty verdict will end his candidacy.

Political commentators said that his candidacy raises the stakes of the trial, tying the verdict to the 2018 elections.

In his 3½ -minute video, Navalny seemed to consciously avoid using the name of the leader who has wielded power in the Kremlin for just about a generation.

“Unfortunately, we’ve already become accustomed to the fact that elections decide nothing,” he said. “Those who are now in power have been there for 17 years and have stopped responding to any criticism.”