Thousands of Google employees, including dozens of senior engineers, have signed a letter protesting the companys involvement in a Pentagon program that uses artificial intelligence to interpret video imagery and could be used to improve the targeting of drone strikes. The letter, which is circulating inside Google and has garnered more than 3,100 signatures, reflects a culture clash ... that is likely to intensify as cutting-edge artificial intelligence is increasingly employed for military purposes. We believe that Google should not be in the business of war, says the letter, addressed to Sundar Pichai, the companys chief executive. It asks that Google pull out of Project Maven, a Pentagon pilot program, and announce a policy that it will not ever build warfare technology. That kind of idealistic stance ... is distinctly foreign to Washingtons massive defense industry and certainly to the Pentagon, where the defense secretary, Jim Mattis, has often said a central goal is to increase the lethality of the United States military. Some of Googles top executives have significant Pentagon connections. Eric Schmidt, former executive chairman of Google and still a member of the executive board of Alphabet, Googles parent company, serves on a Pentagon advisory body, the Defense Innovation Board, as does a Google vice president, Milo Medin. Project Maven ... began last year as a pilot program to find ways to speed up the military application of the latest A.I. technology.