For more than a decade, the U.S. Customs and Border Protection (CBP) has been testing the viability of biometric technology on travelers entering and leaving the country. Now, under the Trump Administration, the number of pilot projects along the Southern border is increasing—leading to fears that such measures may soon pose a real threat to the average American's privacy and civil rights. The pilots have faced criticism from advocacy groups who have raised concerns about the invasiveness of the biometric tracking of physical characteristics such as facial features, fingerprints, DNA, retinas, and others. And on Capitol Hill, lawmakers are debating whether to restrict CBP's use of the technology, after explicitly giving the agency the authority to set up a biometric tracking system for travelers.