North Korea and Russia pose increasingly serious geopolitical threats to the U.S. and its allies. While these rogue nations possess nuclear weapons and formidable conventional forces, they have also used unconventional methods like hacking to attack government institutions and private companies. Add another target to the list of concerns: the Global Positioning System. Built primarily for the U.S. military, GPS is now used by civilians across the globe. Smartphones, personal navigation units, and air-traffic control all rely...

Source: Wall Street Journal November 26, 2017 21:00 UTC