1. Russian efforts to sway the 2016 U.S. election included an extraordinary effort to target black Americans and suppress turnout among Democratic voters, according to a new report commissioned by the Senate.

The report also argued that the Russian presence on Instagram had been underestimated and might have been as effective or more effective than its Facebook efforts. Above, the Russian leader Vladimir Putin, center, with Yevgeny Prigozhin, who was indicted by American prosecutors for his involvement in interfering in the 2016 presidential election.

“Very real racial tensions and feelings of alienation exist in America, and have for decades,” one researcher said. “The I.R.A. didn’t create them. It exploits them,” she added.