“The Russians are using more precise weapons and causing a lot of damage,” she said. “Ukraine has old weapons.” Ukraine only has enough air defense to cover a few cities and has been trying to stopgap the arrival of U.S.-made Patriot batteries, which began arriving this week, with Soviet-era Buk missiles and the medium-range Hawk missile system, which the U.S. Army stopped using in the 1990s and arrived in Ukraine without radars. 

With the Ukrainian military taking hundreds of casualties every week in the Donbas region, former U.S. officials believe that each day Kyiv waits to start an offensive, its military strength is being sapped by the ongoing fight over towns such as the resource-rich Bakhmut. 

“Each day that goes by, we just attrit and the Russians just reinforce,” said Jim Townsend, a former deputy assistant secretary of defense for NATO and Europe. “It builds the case for this offensive getting started sooner rather than later.”