National security

U.S. Defense Secretary Mark Esper, left, and Vietnamese Defense Minister Ngo Xuan Lich talk before a meeting in Hanoi, Vietnam Wednesday, Nov. 20, 2019. Esper is on a visit to Vietnam to strengthen the military relations with the Southeast Asian nation. (AP Photo/Hau Dinh)

Former White House national security aide Fiona Hill, left, and David Holmes, a U.S. diplomat in Ukraine, are sworn in to testify before the House Intelligence Committee on Capitol Hill in Washington, Thursday, Nov. 21, 2019, during a public impeachment hearing of President Donald Trump's efforts to tie U.S. aid for Ukraine to investigations of his political opponents. (AP Photo/Andrew Harnik)

David Holmes, a career diplomat and the political counselor at the U.S. Embassy in Ukaine leaves the Capitol Hill, Friday, Nov. 15, 2019, in Washington, after a deposition before congressional lawmakers as part of the House impeachment inquiry into President Donald Trump. (AP Photo/Jose Luis Magana)

FILE - In this July 16, 2019, file photo, Ernie Field pushes the doorbell on his Ring doorbell camera at his home in Wolcott, Conn. Amazon says it has considered adding facial recognition technology to its Ring doorbell cameras. The company said in a letter released Tuesday, Nov. 19 by U.S. Sen. Ed Markey that facial recognition is a “contemplated, but unreleased feature” of its home security cameras. The Massachusetts Democrat wrote to Amazon CEO Jeff Bezos in September raising privacy and civil liberty concerns about Ring’s video-sharing partnerships with hundreds of police departments around the country. (AP Photo/Jessica Hill, File)

Ambassador Gordon Sondland, U.S. Ambassador to the European Union, arrives to testify before the House Intelligence Committee on Capitol Hill in Washington, Wednesday, Nov. 20, 2019, during a public impeachment hearing of President Donald Trump's efforts to tie U.S. aid for Ukraine to investigations of his political opponents. (AP Photo/Andrew Harnik)

FILE - In this Oct. 11, 2013 file image made from video and released by WikiLeaks, former National Security Agency systems analyst Edward Snowden speaks in Moscow. Snowden says the government is unfairly singling him out in a lawsuit that seeks to block him from profiting off his best-selling memoir. The U.S. says Snowden’s book, “Permanent Record,” violates secrecy agreements he signed when he worked for the CIA and as a contractor for the National Security Agency.(AP Photo, File)

U.S. Ambassador to the European Union Gordon Sondland arrives to testify before the House Intelligence Committee on Capitol Hill in Washington, Wednesday, Nov. 20, 2019, during a public impeachment hearing of President Donald Trump's efforts to tie U.S. aid for Ukraine to investigations of his political opponents. (AP Photo/Andrew Harnik)

Ambassador Kurt Volker, left, former special envoy to Ukraine, and Tim Morrison, a former official at the National Security Council are sworn in to testify before the House Intelligence Committee on Capitol Hill in Washington, Tuesday, Nov. 19, 2019, during a public impeachment hearing of President Donald Trump's efforts to tie U.S. aid for Ukraine to investigations of his political opponents.(AP Photo/Susan Walsh)

National Security Council aide Lt. Col. Alexander Vindman testifies before the House Intelligence Committee on Capitol Hill in Washington, Tuesday, Nov. 19, 2019, during a public impeachment hearing of President Donald Trump's efforts to tie U.S. aid for Ukraine to investigations of his political opponents. (AP Photo/Susan Walsh)