Senator Lindsey Graham (R-S.C.) said the leaking of Gen. Michael Flynn's name to the Washington Post was "just as a bad as what the Russians did" during the 2016 election.
Graham said Monday's hearing further convinced him that the Russians interfered in the presidential election.
He said that whoever unmasked Flynn's name and leaked it to the Post did so for "political purposes."
Graham said he is concerned that the American intelligence system has devolved to a point where a civilian's identity can be captured and used by people with a "political bent" against them.
He said there are two "battlefields" in this regard: Russian interference and the search for the official who unmasked Flynn.
"I want to know what kind of system we have in America," he said.