India is unhappy with the United States selling modern weapons to Pakistan. But as a practical matter, all those weapons, even some F-16 fighters, won't decisively change the military balance. India is, militarily, several times stronger than Pakistan. As a result, Pakistan is putting a lot of effort into building smaller and more reliable nuclear weapons, so that they can be put in missile warheads. This produces a nuclear weapon that can be delivered despite any Indian defenses. India is looking into some of the anti-missile systems available, but for the moment, the missiles have the edge.