https://thinkprogress.org/did-donald-trump-just-write-his-own-articles-of-impeachment-29d3d4b8fff5
"Trump also seems to be under the impression that he is in charge of the investigation into his own campaign and empowered to expand or end it. Trump told Holt that he might “lengthen out the investigation.” Ultimately, Comey’s firing seemed to reflect Trump’s frustration that Comey, in pursuing the investigation, was being “disloyal” to Trump. The New York Times reports that Trump invited Comey to dinner in January and demanded he pledge his “loyalty.” Comey refused, promising only to be honest. The Deputy White House Press Secretary, Sarah Sanders, also linked Comey’s firing today to the Russia probe. Sanders said during her press briefing that she hoped Comey’s firing would help bring the investigation “to its conclusion.” While Trump could theoretically face criminal charges for obstruction of justice, it is not a practical possibility. (Trump, for one thing, controls the Department of Justice.) Therefore, accountability for obstruction of justice would have to be exercised through impeachment. With Republicans in charge of both chambers, impeachment proceedings do not seem in the offing."