The billionaire owner of the New Jersey Nets announced today he would run for president in the country's March elections. That will pit Mikhail Prokhorov against former president and current prime minister Vladimir Putin, generally considered the most powerful man in the country and a shoe-in for another presidential term, likely two.

Prokhorov called it "the most important decision of my life," saying he is running because "society is waking up…Those authorities who will fail to establish a dialogue with the society will have to go."

The 6-foot-9 businessman was referring to last week's protests against Putin and recent parliamentary elections that have been widely accused of being fraudulent. Tens of thousands turned out in Moscow and elsewhere in Russia on Saturday in the largest protests since the days of the Soviet Union.

Forbes puts Prokhorov's wealth at $18 billion, ranking him third in Russia. His wealth comes largely from banking and the sale of his stake in a mining company, forced to sell after he was arrested at a French ski resort in 2007 for providing prostitutes for his guests. He was held for four days, but no charges were filed.

The question now is how genuine is Prokhorov's run. He is not known s a fierce critic of the Putin regime and until September, he was head of Just Cause, a Kremlin-sanctioned liberal party. But when he was ousted from Just Cause, he accused top Kremlin official Vladislav Surkov of being a "puppeteer" and the Kremlin of orchestrating "a raider's attack."

"I can solve that problem by becoming his boss," Prokhorov said today of Surkov.

Prokhorov now has to get 2 million signatures to get on the ballot.

"It is not in my nature to stop halfway," he said. "So for the last two and a half months we sat and worked, very calmly and quietly, and we created all the infrastructure to collect 2 million signatures."

The last time a billionaire challenged Putin politically, he was arrested and imprisoned. Prokhorov was asked today if he feared a similar fate to that of Mikhail Khodorkovsky, in prison since 2003 for tax evasion and embezzlement.

"I'm not doing anything illegal," he responded.