A simple way of thinking of it is like this.
There is a A% chance that 10k passes judicial review and is forgiven
There is a B% chance that 50k passes judicial review and is forgiven
It is understood that A is substantially greater than B.
There is a C% chance that if 10k fails to pass judicial review the mechanism that they are using for blanket forgiveness will be restricted or lost
There is a D% chance that if 50k fails to pass judicial review the mechanism that they are using for blanket forgiveness will be restricted or lost
It is understood that D is substantially greater than C.
How do you get these percentages? It's just a matter of making educated guesses. That's all we have in a 6-3 world where all established legal logic appears to go out the window on most every case they are hearing.
Yes you are correct that the only way to know is to do it. The problem is that if you try it and get the worst result not only will the debt not be forgiven, it may not be possible to even try again and go for a lower number. So you have to balance the risk with the reward. Is the benefit of the extra forgiveness worth risking any forgiveness? Is the increased risk that it will not be possible to try again if it fails worth the extra benefit if it does pass? Now with a court that is poised to gleefully get rid of roe the risk for this to get shot down seems higher than ever.
If anything, Roe shows that we should've maximized the most amount of abortion rights possible in previous years when Democrats had full control, since sticking with the compromise of "Roe is settled law" and focusing all political efforts on "uh, nominate judges?" just led to a massive erosion of rights in large parts of the country well before this year, and still led to Roe likely being overturned.
I guess this is where we'll have to agree to disagree, since I think trying to quibble over and calculate "chances of getting overturned based on dollar amount" is a fundamentally flawed approach to take on this topic. How is that even a measurable thing to make an "educated guess" about? Is there any data on other loan policies that says "the conservative Supreme Court is ok if you do X, but not X + 1" and can be used to inform this approach? Federalist society conservatives are morally and philosophically against the federal government doing anything like this, no one's fooling them by prematurely tweaking dollar amounts to try and find some "reasonable" number to use beforehand that will avoid the inevitable political fight.
But I guess that gets to a larger point that this type of approach to politics seems like a fundamentally amoral one. If there's no obvious
legal barrier preventing someone from forgiving all of it (the current answer seems to be "maybe, maybe not"), a person who finds the idea of student debt immoral would just…get rid of it when they have that power. And for the politics of it, they would make their case for why, and build a case for it, organize people in support of it, flood media with all the possible benefits, and try to bring people to your side. That's one approach to this issue.
The other approach of tweaking numbers to find some "sweet spot" is fundamentally an approach of someone who thinks student debt is basically fine, but it's maybe just a little bit egregious in some cases. This is the approach of Joe Biden, which makes sense, based on his history (especially on this topic, considering he's one of the main people legislatively responsible for the student debt crisis). Fundamentally, I think that's a far more obvious reason for his "incrementalism", and not some sort of clear headed probability calculation.
"Incrementalism" (in the sense of trying to take smaller steps toward an ultimate long term goal) makes sense when you're trying to find a way to build enough power to do something. "Incrementalism" when you already have the power (or at least, a good chance of wielding that power) to do the thing seems kind of nonsensical?
If anything, forgiving all debt is a more rational "incrementalism" goal, since that would put more pressure on the legislature to actually address college costs on a more fundamental level, because that increases the number of potential pissed off borrowers if they just let it get overturned without any legislative response. If the incrementalist goal was actually "eliminate student debt entirely" that seems like a wiser way to wield the legal power you have as president.
If we are talking the current SCOTUS, the chance that 10k or 50k is overturned is pretty much the same. They'll decide on whether the President can do it all, most likely. This SCOTUS won't worry about the amount.
Yeah, this seems to be the actual view that matches up with what conservatives actually think of federal actions like this. Like, they didn't hate the ACA because the subsidies were too high, they hate it because their long term, well funded, and well established political project and moral code involves dissolving most of the federal government and kicking everything to individual states. The differences between the design of the ACA or single payer doesn't matter to them, they're all "socialism".