Protesters hold placards reading 'No Abe!' earlier this month during a demonstration against Japan's removal of South Korea from a list of trusted trading partners in Seoul.
Jean Chung/Bloomberg via Getty Images
This photo released by the U.S. Defense Department shows the launch of a conventionally configured ground-launched cruise missile at San Nicolas Island, Calif., on Sunday.
U.S. Department of Defense
The U.S. Navy Blue Angels flight demonstration team performs a flyover above the Lincoln Memorial during Independence Day celebrations on July 4 on the National Mall in Washington, D.C..
Acting Secretary of Defense Patrick Shanahan listens as President Trump speaks during a signing event for "Space Policy Directive 4" in the Oval Office of the White House in February.
Acting Secretary of Defense Patrick Shanahan was cleared by the Pentagon's Inspector General of allegations of ethics violations. Shanahan is seen here testifying at a House Armed Services Committee hearing last month.
Drew Angerer/Getty Images
Members of the U.S. military install multiple tiers of concertina wire along the banks of the Rio Grande near the Juarez-Lincoln Bridge at the U.S.-Mexico border in Laredo, Texas, in November.
Defense Secretary Jim Mattis announced his resignation on Thursday, following a decision by President Trump to withdraw American troops from Syria. He'll be replaced by Deputy Secretary of Defense Patrick Shanahan starting in January.
A border protection officer stands next to a recently upgraded section of fencing at the U.S.-Mexico border in Calexico, Calif., on Friday. The Pentagon says it will send 5,000 U.S. troops to the border.
Mark Ralston/AFP/Getty Images
The Pentagon only recently made cybersecurity a priority, the Government Accountability Office says in a new report, which found vulnerabilities in weapons that are under development.