If confirmed, he would replace outgoing Secretary Kristi Noem, who was fired earlier this month amid mounting criticism of her leadership of the Department of Homeland Security.

GOP Sen. Markwayne Mullin's confirmation hearing to lead DHS kicked off with criticism of his conduct by GOP Sen. Rand Paul of Kentucky, the head of the committee that would approve his nomination.

The top Republican on the Senate committee considering Sen. Markwayne Mullin’s nomination to run the Department of Homeland Security criticized his “machismo” at the confirmation hearing on March 18.

A look at key moments as Markwayne Mullin appears before the Senate for his Homeland Security confirmation hearing.

The Republican chairman overseeing hearings on Senator Markwayne Mullin’s nomination to lead the Department of Homeland Security blasted the Oklahoma Republican for “anger issues,” arguing they disqualified him from leading an agency enmeshed in controversy over aggressive tactics.

Senate Homeland Security Chairman Rand Paul criticized Senator Markwayne Mullin during his confirmation hearing, calling him a "man with anger issues."

Markwayne Mullin, the White House pick for homeland security secretary, made a case to fellow senators Wednesday that he would be a steady hand for a department roiled by controversy under Kristi Noem,

Sen. Markwayne Mullin appeared before the Senate Homeland Security & Governmental Affairs Committee on Wednesday for a confirmation hearing to replace DHS Secretary Kristi Noem. CBS News congressional reporter Taurean Small has more.