This week's confirmation hearings for homeland security secretary and transportation secretary were notable for something not discussed: the fact that the two departments have failed for 12 years to comply with presidential orders to eliminate one of the most serious threats to the security and economy of the United States. America's Global Positioning System is a technological miracle and our gift to the world. Cellphone networks, first-responder radio systems, computer and financial networks, even electrical grids - all depend on GPS. At the same time, GPS signals are weak and easy to disrupt. This combination of overwhelming dependence and vulnerability is why Department of Homeland Security officials have called GPS a "single point of failure for critical infrastructure." In a 2004 national security directive, President George W. Bush tasked the Transportation Department to work with Homeland Security and other departments to acquire and operate a backup system to prevent [GPS system failure]. President Obama reaffirmed this order in 2009. Yet, despite announcements in 2008 and 2015 that the nation would establish a high-powered terrestrial ... system to work hand in hand with GPS, nothing has been done. So our national danger grows by the day. Previous administrations have ... failed to act. Let's hope the Trump administration [does] what the previous two have only promised: protect America's national and economic security with a difficult-to-disrupt complementary and backup system for GPS.