Senate Homeland Security chairman: Leaving Iraq set path for ISIS

Senate Homeland Security Committee Chairman Ron JohnsonRon JohnsonSenate rivals gear up for debates The Trail 2016: Trump seizes on Charlotte violence The Hill's 12:30 Report MORE (R-Wis.) blasted President Obama on Sunday, saying it was a mistake for him to pull out of Iraq because it laid the groundwork for the Islamic State in Iraq and Syria (ISIS).

“The historic blunder of President Obama was leaving Iraq,” Johnson said on CNN’s "State of the Union" with Jake Tapper Sunday.

“After all the sacrifice, after the stabilization of Iraq, we bugged out, and as a result, that coalition disintegrated, and ISIS was able to rise from the ashes of what was a defeated al Qaeda in Iraq," said the Wisconsin Republican.

Johnson also said the U.S.’s critical infrastructure is vulnerable to cyberattacks and potential terrorist attacks.

“We are not taking this threat seriously enough, and it’s highly concerning,” he said.