Secretary of Homeland Security Kristi Noem said that authorities believe the suspected shooter who they say opened fire on National Guardsmen in Washington, D.C., last week might have been radicalized after he arrived in the United States. Sen. Chris Van Hollen, D-Md., said Sunday he believes "it's very possible there was a war crime committed" in the administration's first strike against an alleged drug trafficking boat in the Caribbean Sea in September. Roundtable: Former DNC chair Donna Brazile, former New Jersey Governor Chris Christie, Democratic strategist Faiz Shakir, and communication analyst and pollster Frank Luntz.

"What is President Trump's theory of the case? Is it regime change? We've got -- an amassed force almost unprecedented in the region, and I think the president needs to come to Congress and the American people if his goal is to further increase pressure on Maduro and potentially launch forces," Virginia Sen. Mark Warner told ABC News' "This Week" co-anchor Martha Raddatz. "The president has not been, been clear, and he's not certainly been communicating with, with Congress, and I think he has been certainly escalating, both the rhetoric and certainly the presence in the area," Turner said. Ohio Rep. Mike Turner, a Republican on the House Armed Services Committee, also took issue with the lack of information the administration provided. Roundtable: Former DNC chair Donna Brazile, "New Yorker" staff writer Susan Glasser, "Puck" chief Washington correspondent Leigh Ann Caldwell, and RNC senior adviser Danielle Alvarez, now an ABC News contributor making her "This Week" debut.