> The US Supreme Court should—in fact must—declare this “impeachment” unconstitutional. <
I must respectfully disagree. The Supreme Court must not interfere in any impeachment. The president appoints the Supreme Court members. So it is conceivable that a president would have majority support on the Supreme Court. If the Supreme Court could interfere, then such a president could not be impeached. No matter what the House said, the Court could just say no. Then we’re back to the tyranny the Founders wanted to avoid.
As for the “high crime” requirement, in the language of the day that meant any misbehavior by a high public official. Benjamin Franklin even once remarked that a president could be impeached just for being rude!
You mentioned that impeachment gives the Legislative Branch de facto control of US presidential elections. That is an excellent point. The Founders tried to avoid that problem by requiring the high hurdle of 2/3 needed to convict in the Senate.
But that safeguard is weakened now that we have the direct election of senators.
I think the best thing I have learned in all this is the Framers never intended impeachment be essentially a Parliamentary “Vote of No Confidence” which Pelosi has turned it into.
You almost got it right but not entirely.
The president does not appoint the Supreme Court justices. He nominates them and the Senate vets and confirms (or not) his nominees.
So it is not the president that has the sole power to appoint SC justices. The legislative branch, by way of the Senate Judiciary committee and then the full Senate, have a big say in the matter as well.
President Donald Trump may be able to have a court or SC dismiss the impeachment charges prior to any action by the Senate. The grounds could be the judiciary’s role in determining the definition of “high crimes,” and whether the impeachment charges voted on by the House constitute “high crimes” under the Constitution. The president could seek a declaratory judgment.
There has been talk of doing this because the charges or articles brought by the House don't rise to the high crimes and misdemeanors required by the Constitution.
There is nothing to stop the president from going to court to stop this weak impeachment case.