They should have deadlined that nonsense thru legal

Goes around getting into new things, causing problems, starting trouble. Then the adults have to come in and fix the stuff he breaks.

The military enforces enlistment contracts so recruits can’t just quit. So, too, recruits shouldn’t be separated from the service & their enlistment contracts voided merely because Trump has a tantrum. It’s breach of contract.

They are getting discharged because they were unable to obtain a security clearance.

They enlisted under a program that opened up recruitment to categories of immigrants not usually eligible because the military needed specific skills, in most cases language skills.

Pretty much every MOS that requires lanaguge skills- intelligence, interrogation, etc- requires a security clearance with most of them requiring a TS.

These recruits have been sitting in limbo, never having shipped to Basic Training, because they can’t obtain a cleanrce. Most are in the USAR just holding a slot in a unit but unable to actually start training.

The contracts are clear that if you can’t get a clearance you are not eligible to ship to Basic Training. They had been shipping recruits under this program, known as MANVI, to Basic while the clearance process was still happening but they had so many with issues that cost a ton of money only to end up discharged they changed the process several years ago to require a clearance before they ship to Basic to be sure they were eligible.

So these recruits are actually being treatment no different than anyone else who loses eligibility before they ship to Basic. A recruit who joins the USAR and is drilling but then gets in legal trouble, gets injured, gets pregnant etc will also be discharged instead of being sent to Basic.

Some of my knowledge also comes from
23 years in the USAR and knowing a current USAR recruiter who I have spoken to about this. But these are a good start for you:

https://partner-mco-archive.s3.amazonaws.com/client_files/1530903733.pdf

https://www.vox.com/2018/7/9/17540114/immigrants-discharged-kicked-military-daca

https://www.military.com/daily-news/2018/04/15/recruits-bureaucratic-limbo-citizenship-program-suspended.html

https://www.militarytimes.com/news/your-army/2017/12/24/new-in-2018-for-foreign-recruits-the-new-year-brings-few-answers/

In that first VOX article they were a little unclear when they say that some were booted “out of uniform” or after they “stared participating in training”. What they are talking about is USAR enlisted who are in a kind of limbo before they go to Basic Training. They show up for drill either at their future unit or at a special unit that trains them before Basic Training, but they are not fully enlisted and can only do a very limited amount of training.

But it’s essentially that the ones being discharged are all one ones who couldn’t get a security clearance. For every case I’ve seen them go into specifics the people have been waiting on a cleanrce a year or longer.

The Army sets an absolute maximum time they will allow at 3 years, but after 1 year a commander retains them at their discretion and can go ahead and discharge them at that point before the 3 year mark. Often they do (not just in this case but also for things like injuries waiting to heal, pregnancy etc) because while these enlistees are in this limbo they can’t deploy with the unit and they can’t particpate in most of the training, but on the books that position has been filled and they will also not be getting anyone else to fill that slot. So when someone sits in those positions for years instead of the typical few months before going to training they are essentially making the unit weaker because the others have to do the job for that slot. And if the unit faces possible deployment in the next couple years it can mean that they don’t get anyone in that position and have to, at best, fill it with a last minute crossover who they have never worked or trained with.

So having people sit in limbo for years occupying a slot in a unit is damaging to the unit in some cases. That means that the commanders often have to make tough choices.

If they're security risks, I'd think the Pentagon would appeal all the way to the Supreme Court.

Their lawyers probably argued about technicalities in how the discharges were done. I’ve seen that before, there are lawyers who specialize in nothing but contesting unwanted discharged or the characterization of a discharge who know the bureaucracy and how to nitpick the paperwork.

I’m willing to bet the recall is for nothing more than to do the paperwork in a way that avoids the lawsuits.

Or they may just let the 3 year clock run out while waiting on a clearance and then legally they must be discharged.

Or they may choose to allow them into an MOS that doesn’t require any clearance, despite the terms of their enlistment making it clear that wasn’t an option due to the special considerations they got to begin with.

Why is this time period any different? Because the recruits aren't white, western Europeans?

Anyone in the US on a green card as a lawful resident alien can enlist as long as they meet all other eligibility criteria. Last time I was at an Army Basic Training graduation they did the citizenship ceremony for 5 or 6 new Soldiers and Citizens right there.

None of that has changed.

The only recruits affected by this are ones that came in under a special program known as MANVI. This program opened up enlistment to people here in the US but not normally eligible to enlist- those on student visas, work visas, etc. To qualify they had to have specific skills badly needed by the military, either high level medical training or language skills that were needed.

A typical recruit going into a job that requires a clearance will be allowed to start Basic Training after enough time has passed from the start of the clearance that they statistically are likely to have a clearance granted by the time they graduate. The few who don’t go into a “holdover” status where they simply hang around doing busy work getting paid. If the clearance comes in they go on to the MOS school, if not they typically get discharged and the Army has wasted a ton of money.

Problems arose with a high number of the MANVI recruits failing to get clearances and also some who were serious security risks being found after they stared training. So the Obama administration, not Trump, put in a new rule. If you enlist under MANVI your clearance must come back approved before you go to Basic Training.

The ones being discharged have been waiting for clearances for a year or longer and are either discharged when they get denied one or when the USAR unit Commander they are assigned to decides they have given them enough time and it’s in the best interests of the unit and the Army to discharge them and open that position to an applicant who can actually qualify in a timely fashion.

it's more complicated than I ever thought perhaps because the headlines don't delve into detail

But sensational headlines get attention. And “immigration troops purged” draws a lot more attention than “small percentage of immigrat recruits who can’t get security clearances not allowed to go to Basic Training”

They were viewed in much the same way back then as many Cons view immigrants today. They were fine for cannon fodder, but when it's time for a job, Irish Need Not Apply.
"Irish racism in Victorian Britain and 19th century United States included the stereotyping of the Irish as violent and alcoholic." Sound familiar?

https://en.wikipedia.org/wiki/Anti-Irish_sentiment#19th_century