Ukraine is increasingly worried about securing more U.S.-made Patriot air defense systems, as stockpiles sent during the Biden administration are drying up and the new administration is resistant to sending more, according to six Ukrainian and Western officials. While Russia bombards Ukraine with drones and cruise missiles, it is the ballistic missiles that are the most feared, and they can be reliably countered only by Patriot missiles. Ballistic missiles travel several miles per second, and they obliterated half of Ukraine’s power capacity in strikes on power plants. Their speed and size, plus the fact that they are difficult to intercept,...