His point is Trump has the right to fire Comey for any reason. To have obstruction, you have to have 1) underlying crime 2) intent to cover it up, which he doesn’t believe you have here.
Via Newsmax:
A dangerous argument is now being put forward by some Democratic ideologues. Namely that President Trump should be indicted for the crime of obstructing justice because he fired FBI Director James Comey.
Whatever one may think of the president’s decision to fire Comey as a matter of policy, there is no legitimate basis for concluding that the president engaged in a crime by exercising his statutory and constitutional authority to fire director Comey. As Comey himself wrote in his letter to the FBI, no one should doubt the authority of the president to fire the Director for any reason or no reason.
It should not be a crime for a public official, whether the president or anyone else, to exercise his or her statutory and constitutional authority to hire or fire another public official. For something to be a crime there must be both an actus reus and mens rea — that is, a criminal act accompanied by a criminal state of mind.