The soaring demand for Patriot missiles, from the Middle East to Ukraine

Ukraine's defenses have held the line on most fronts, but there's one glaring weakness -- Russian ballistic missiles. Ukraine is desperately short of U.S.-made Patriot air defense missiles needed to defend against the Russians.

The U.S. and its partners depend on Patriot interceptors to shoot down incoming ballistic missiles. But Russia and Iran are firing their weapons at rates far higher than Patriots can be produced.