The early warning radars on Greenland are key to defending the U.S. against nuclear attack, but they're vulnerable to hypersonic missiles, critics warn.
Putin emphasized that the maneuvers had been planned in advance, but they came shortly after the prospects of a meeting with Donald Trump fell through.
Variants within the same plane model, incompatible support equipment and a lack of shared data create barriers to interoperability, a Rand report warns.
Decades after the Army abandoned the Pentomic concept, a defense expert argues such a concept may provide a solution to the battlefield problems of today.
