By making this argument?
"President Donald Trump's lawyers argued in a confidential January letter to special counsel Robert Mueller that the President cannot illegally obstruct the Russia probe because he, as the top law enforcement officer, has authority over all federal investigations, The New York Times reported Saturday.
The 20-page letter from Trump attorney Jay Sekulow and then-Trump lawyer John Dowd, which CNN reported on last week and the Times has obtained, says that Trump could not possibly have committed obstruction in the Russia investigation because the Constitution empowers him to "terminate the inquiry, or even exercise his power to pardon if he so desired."
Trump's "actions here, by virtue of his position as the chief law enforcement officer, could neither constitutionally nor legally constitute obstruction because that would amount to him obstructing himself," Dowd and Sekulow wrote.
The two argued that "no President has ever faced charges of obstruction merely for exercising his constitutional authority" and that a President can "order the termination" of a Justice Department or FBI investigation "at any time and for any reason."
https://www.cnn.com/2018/06/02/politics/trump-special-counsel-memo-avoid-subpoena/index.html