Glenn Spencer is an American political and anti-illegal-immigration activist who serves as president of American Border Patrol.
In the 2000s Spencer gained media attention when he converted his ranch on the Arizona and Mexico border into a research and testing facility, seeking low-cost ways to improve border security, such as infrared cameras, aerial drones and motion detectors. Spencer's researchers developed a system for greatly improving the sensitivity and accuracy of seismic detectors, called SEIDARM, which he patented  and offered for sale to the US federal government.
In 2001, he started warning of a “Mexican takeover of the southwestern United States,” and made a video titled Immigration: Threatening the Bonds of Our Union, which he delivered to every member of Congress.
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