Impeachment doesn't require a crime

Instead of sticking to the most defensible case for a Senate acquittal of Trump, Republicans from the president on down are making arguments that range from the implausible to the embarrassing.
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Hence the claim now being advanced half-heartedly by Republicans that presidents cannot be impeached for any abuse of power unless that abuse took the form of a criminal violation of a statute. The consensus of those who have studied this question is to the contrary. Jonathan Turley, the Republicans’ star witness in the House hearings about the constitutional issues raised by impeachment, has repudiated this view. Attorney General William Barr has in the past denied it. The Founding-era debates about impeachment are clear that Congress was to be able to remove a president from office if he had exercised his legal powers in an abusive way. One example that came up during those debates: What if the president tacitly encouraged a crime and then pardoned the perpetrator? The pardon power is arguably unreviewable, and certainly very nearly so. It was left to the judgment of a majority of the House and a supermajority of the Senate, as always under the supervision of the voters, whether a president’s conduct had rendered his continuation in office intolerable.