Precedence of the United States

One of the major faux-concerns about the Senate Impeachment Trial that Republican like to wring their hands over is that the trials sets a bad precedent, because once you do this then the door is opened and any former president could impeached for anything.

Well...there's that and then there's reality.

First of all, Trump was impeached while he was president.  That's not only absolutely constitutional, of course, it's how impeachment is done.  At issue is when the trial is held.  Impeaching someone when he is a former president is a totally separate matter.  It's also likely highly unconstitutional. And so, no, you couldn't impeach any former president.

Secondly, to impeach a president you need impeachable offenses.  And while, sure, a majority party could always impeach a president of the other party for any reason they want -- but the American public has show it takes its presidents and impeachment seriously.  (Consider how split the country was when Trump was impeached the first time for bribing a foreign government.  And even with the issue this time being insurrection overthrow the government, still only 56% country were initially in favor of Trump being impeached.)  So, if a party impeached a president for any minor, insignificant matter out of political irritability, I suspect that the public would be outraged and the party would face major consequences in the next election  Which is why there had only been two impeachments in U.S. history before Trump.  What a party "could" do is wildly different from what a party would dare do at its own peril.  And this doesn't even take into consideration that the trial would still require two-thirds of the Senate to convict.  Trump incited an insurrection and it's not certain he'll even get 55% of the vote to convict.  Imagine a party trying to convict an out-of-office president driving for something meaningless.  In the end, people can always do whatever they want that they have the right to.  A person has the right to buy a bulldozer in order to crack open a single peanut.  But it would be monumentally stupid with family consequence from one's spouse and neighbors, and so it tends not to be ever done.

But hey, they could do it.  Let's say they do.  Let's say a particular party just really wants to screw with a former president and impeach him at the very end of his term for something petty -- okay, let's say for driving with an expired license or even something worse, but still nothing at the level of bribery or sedition, perhaps the arguable misuse of funds -- and then holds the trial when he's out of office.  Okay.  And this would get them...what??  The penalty for impeachment is that you're removed from office.  This mythical president in question is already out of office.  So, what on earth would the point be?  Never mind the political consequences for the party who did the impeaching. What do they get for this "already out-of-office" trial?  Other than outrage against themselves from the country. The point for having a trial for Trump when out of office is he tried to overthrow the U.S. government -- and you absolutely do want to hold him accountable for that, because if you don't, then another president could try the same thing knowing there's no political risk for him.  So, again, yes, holding a Senate Impeachment Trial when a former president is out-office could be done.  The downside is that there is absolutely nothing to be gained, and every member of the party risk their own political future.

So, fourth, that brings up the question of if Democrats set the precedent and had a Senate Impeachment Trial of Trump when out of office, it would open the door to what Republicans could do.  The problem with that is that the door has always been there to do that very thing.  There has never been anything stopping a party from impeaching a president at the end of his term and having a Senate Impeachment Trial when he's out of office.  Any party could do it whenever they've wanted to throughout U.S. history.  "Precedence" was never needed.  There was no precedence when Andrew Johnson became the first president impeached.  But it was in the Constitution.  And as for this precedence -- honestly, I don't think today's Republican Party cares on tiny whit about precedence.  Not having precedence didn't stop Mitch McConnell from blocking Barack Obama's Supreme Court nomination of Merrick Garland.  Nor did it stop him from breaking precedence and rushing through the approval of Amy Coney Barrett for the Supreme Court barely a month before the end of Trump's term in office.  In fact, there was precedence that she not be approved.  But Republicans were okay with that.  So, the whole "This would set a precedence and open the door to a slippery slope" gambit is a joke argument that even Republicans themselves giddily don't believe in.

And that leaves the question of, if this actually does open the door to set a precedence, what the precedence would actually be,

And the precedence would be that if a U.S. President was impeached for inciting insurrection to overthrow the government, he could be tried in the Senate when out of office.  And, y'know, as far as precedences go, I think that's A Really Good One.  And personally, I'm all for it -- whoever the president is, whatever his party.  Absolutely great precedence.

If a president commits some acts at the end of his term that puts the entire country and democracy at risk, yes, that would be a very good precedence to set to impeach him and have a trial even if he is out-of-office.

Fair enough.