Back when I used to be a lawyer, there were times when I had to argue a very tough case.
When I represented people accused of crimes, I never asked "Did you do it?". I viewed that question as needlessly confrontational and frankly, irrelevant. My job was not to prove that the defendant "didn't do it". It was to make sure that the state didn't put anyone in jail without giving them a fair trial where all of the state's evidence was vigorously tested. If the prosecutor couldn't prove her case beyond a reasonable doubt, my client deserved to be found not guilty, whether he ate the nuns or not. And yes, I probably did represent a disproportionate number of nun eaters back in the day.
Instead, I asked a different question upon meeting a new prospective client. "Why do the police THINK you did it?". This invites the defendant to tell me about all of the evidence the police may have without forcing him into some awkward confession or (potentially) starting off our relationship with a lie.
Sometimes the defendants were very forthcoming, which it really was in their interest to be. But others saw it differently.
I remember one case where the defendant was accused of robbing a 7-11 in Allentown. When I asked him why he had been arrested, he said "I have no idea". When I tried to probe further into why the police might be thinking he was involved, he doubled down. "They got nothing. I don't know why I'm even involved in this". When I asked if he could think of one single thing that might be pointing in his direction as the one who committed this crime, he said "Nope" and then volunteered that he was sure he was arrested at random.
I sat down at his preliminary hearing feeling very confident. That confidence dissipated somewhat as the prosecution presented three witnesses who positively identified my guy. It further sank when they introduced all of the 7-11 products that they had found at my client's apartment. I became despondent when they showed the surveillance video of my client actually committing the crime, and moved towards despair as they read his signed confession in open court.
OK, so maybe my client wasn't completely forthcoming with me. But he had still paid me, mostly in 7-11 coupons and Slim Jims, which shouldn't have been a red flag in retrospect, and I had to say something. So when it was my turn to speak I blurted out that this case was "an OUTRAGE!!". Whenever I wanted to stall for time, I barked out that something or other was an OUTRAGE!!. And when I wanted to confuse the judge, I could yell "Kangaroo!!", which usually did work, at least for a few seconds.
I was reminded of this story when I listened to Donald Trump's lawyer argue that as a former President, Trump had absolute immunity for any criminal act he might have committed while president. The attorney argued that the only remedy for a President who, for example, has his political opponents murdered, or sells our nuclear secrets to the Russians, is impeachment by the House and conviction by the Senate. Only after THOSE things have occurred can the President be charged with a crime.
The Trump lawyer arguing this had an even harder case than I did with my 7-11 burglar. Has had to stand before three appellate judges and argue that a president could order Seal Team 6 to murder his political opponent and still not be charged unless he had been previously impeached. As good as this hypothetical was, there is an even better one. Given Trump's claim that conviction by the senate is required to hold him criminally responsible for anything, he could publically order Seal Team 6 to murder any US Senator who says he is voting for conviction, and their families, and their campaign managers, which would really hurt. Again, under Trump's theory of the law, there is absolutely nothing the justice system could do about any of this.
Of course, we all know that threats of murder probably wouldn't be necessary to ensure a senate acquittal. We have become so partisan today that getting the requisite number of Republicans to abandon Trump for ANYTHING would be close to a physical impossibility. I mean, 57 Republicans voted to acquit Trump of conjuring up a violent attempted coup to overturn a free and fair election so he could stay in power indefinitely. If the senate won't convict him for that, there's very little reason to believe that there is any conduct they would feel crossed the line.
And this gets to the main reason that Trump's argument must fail. The criminal justice system is supposed to be non-political. People should be charged or not charged based on the facts and the law without fear or favor. But impeachment has always been, and is certainly now, an inherently political process. We cannot have a partisan, political process as the final arbiter of criminally unacceptable presidential conduct.
Elected politicians decide what the laws are, but if we allow them to determine if and how those laws are enforced, we will inevitably have the prosecution of the unpopular, while we look the other way for the favored. We will see team red prosecuting team blue while protecting it's own, and vice-versa (perhaps). A president who controls the base of his party will control the votes of those officials who must appeal to the base for their jobs, will be bullet-proof and untouchable. And that is a sure road to dictatorship.
Trump's argument would literally rip the blindfold off of Lady Justice. Just like my client ripped yodels and ho-hos off the shelves of that 7-11 (which he still denies). And that is not something a nation that claims to live by the rule of law can tolerate.