Justin Amash thinks Donald Trump is guilty of "impeachable conduct," and he is absolutely right. Impeachable conduct is whatever the House of Representatives decides it is, a point the president's defenders and some of his critics seem determined to obscure.
The House impeached Bill Clinton for lying under oath about oral sex, and the conduct described in Special Counsel Robert Mueller's report is more troubling and consequential, even if it does not amount to a crime that could be proven beyond a reasonable doubt. When Amash, a five-term Michigan congressman, became the first Republican legislator to make that point, the reaction revealed how determined his colleagues are to evade their responsibilities.