MOSCOW—Lawyer and anticorruption activist Alexei Navalny has leveraged the tools of social media and online video to present one of the most serious domestic political challenges to Russian President Vladimir Putin in recent years. On Sunday, Mr. Navalny cemented his position as the most prominent figure in Russia’s fractured and marginalized opposition by spurring antigovernment marches around Russia that drew thousands.

Source: Wall Street Journal March 27, 2017 19:30 UTC