Hackers have already accomplished goal of undermining Americans' confidence in elections, security expert writes

The security threat to America's election systems is real and ongoing, but foreign hackers appear to have already accomplished one goal: to undermine voters' confidence in the electoral system, national-security expert Susan Hennessey writes for the Brookings Institution. Almost eight in 10 Americans are at least somewhat concerned about potential hacking of U.S. voting systems, according to a University of Chicago poll.

Hennessey, a governance fellow at the Washington, D.C. think tank, discusses election security in a short video: