Justin Amash, the first Republican Congressman to call for Trump's impeachment, today released another analysis:

[twitter.com]
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:

1. They say there were no underlying crimes.

In fact, there were many crimes revealed by the investigation, some of which were charged, and some of which were not but are nonetheless described in Mueller’s report.

2. They say obstruction of justice requires an underlying crime.

In fact, obstruction of justice does not require the prosecution of an underlying crime, and there is a logical reason for that. Prosecutors might not charge a crime precisely because obstruction of justice denied them timely access to evidence that could lead to a prosecution.

If an underlying crime were required, then prosecutors could charge obstruction of justice only if it were unsuccessful in completely obstructing the investigation. This would make no sense.

3. They imply the president should be permitted to use any means to end what he claims to be a frivolous investigation, no matter how unreasonable his claim.

In fact, the president could not have known whether every single person Mueller investigated did or did not commit any crimes.

4. They imply “high Crimes and Misdemeanors” requires charges of a statutory crime or misdemeanor.

In fact, “high Crimes and Misdemeanors” is not defined in the Constitution and does not require corresponding statutory charges. The context implies conduct that violates the public trust—and that view is echoed by the Framers of the Constitution and early American scholars.