People who say there were no underlying crimes and therefore the president could not have intended to illegally obstruct the investigation—and therefore cannot be impeached—are resting their argument on several falsehoods:
According to Amash's reasoning, Trump's defenders "say there were no underlying crimes," "say obstruction of justice requires an underlying crime," claim Trump should be able to end a "frivolous investigation," and attempt to redefine "high crimes and misdemeanors." But there were "many" crimes — not that obstruction of justice charges require them, Amash continues in his thread. The "high crimes and misdemeanors" portion of impeachment proceedings aren't even "defined in the constitution," Amash also said, adding that a president just has to commit "conduct that violates the public trust."
Amash's Saturday tweetstorm has already led Michigan state Rep. Jim Lower (R) to announce he'll primary Amash next year. House Minority Leader Kevin McCarthy (R-Calif.) told Fox News that Amash "just want to have attention," though as CNN's Haley Byrd said in a tweet, that doesn't usually seem to be Amash's top priority. Kathryn Krawczyk