What We're Following This Afternoon

Florida death penalty system ruled unconstitutional: The Supreme Court, in an 8-1 ruling, said the system used by the state to sentence people to death hands too much power to judges—and not enough to juries. Justice Samuel Alito dissented. Update: More here

Istanbul attack update: Turkish officials say the suicide bomber who killed 10 people and wounded 15 others in the Sultanahmet district was a Saudi-born member of ISIS. They earlier said he was Syrian. All the victims were foreign, and nine of the 10 were Germans, the officials said.

Powerball jackpot grows: It’s now up to $1.5 billion (not a typo). A single winner who takes a lump-sum payment will take home $930 million. The odds of winning are one in 292.2 million. The New York Times puts that in perspective: “If you printed out the name of every United States resident on individual pieces of paper, put them in a giant bowl and selected one at random, the odds of picking President Obama are not far from the odds of winning the Powerball.” The next drawing is tomorrow at 10:59 p.m.

Our headlines from the morning are here.