"Why does the Mueller team have 13 hardened Democrats, some big Crooked Hillary supporters, and Zero Republicans? Another Dem recently added ... does anyone think this is fair? And yet, there is NO COLLUSION!," Trump wrote on Twitter.
Graham said on "State of the Union" that the Senate Judiciary Committee should hold a hearing on McCabe's firing to "make sure it was not politically motivated."
"I think we owe it to the average American to have a hearing in the Judiciary Committee, for Mr. Sessions, Attorney General Sessions, comes forward with whatever documentation he has about the firing and give Mr. McCabe a chance to defend himself," Graham said. "I believe when it comes to this issue, we need as much transparency as possible, to make sure that it was not politically motivated.