US Secretary of Defense Lloyd Austin warned Russia on Wednesday that any further violations of Ukraine’s airspace will lead to a response. He also reaffirmed that lines of communication remain open.

A new simulation by researchers at Princeton University paints a terrifying picture of what a plausible US-Russian nuclear war would look like. The simulation uses realistic nuclear force postures, targets and fatality estimates to show what would happen in the first few hours of such a conflict.

Despite their bluster and Cold War-era levels of brinksmanship, the United States and Russia have little in common militarily. The American military’s globe-spanning force would clobber the Russian military in any toe-to-toe conventional fight, experts agree. But modern wars are rarely such fights. Instead, geography, politics and terrain inevitably give one side an advantage. Today the United States spends 10 times more on national defense than Russia, operates a 10-carrier fleet, maintains a broad technology edge and has vastly superior power projection capabilities around the world.

Nevertheless, the confrontation over Ukraine has revived Cold War-levels of suspicion, antagonism and gamesmanship between two nuclear-armed giants. It’s also renewed public concern about the future of NATO and heightened anxiety about what Putin might do next. Still, the latest Pew Research Center poll shows that partisan attitudes toward Russia have been stabilizing, and deeply unfavorable views of Moscow have declined from their peak in 2020. Democrats, older Americans and those who think it’s important for the U.S. to consider the interests of other countries give more support to NATO.