I don't think it's possible to challenge a presidential pardon. Challenging distributing funds by presidential order is something very different - power of the purse constitutionally is in legislature's hands, and taking it from there, even in the current "anything goes" climate, is a pretty serious deviation. OTOH, the power of pardon has always been with the President and nobody would question it. There were some questionable pardons, for sure, but nobody doubts Biden can do it. There's no need for legal opinions to establish such right - it's long established.

But a poorly executed mass pardon can harm Biden's presidential popularity, which is highly correlated to getting laws passed by Congress. Skimming the contents of this academic book [0], it doesn't look like there has been a major mass pardon in the 20th century other than Carter's?

There have been large state mass pardons recently, but most of those are of a different political beast -- i.e. at the end of a term, and are (usually, I assume) on a case-by-case basis, i.e. 500 individually researched cases, not all 500 felony drug users. And that has its own political problems that aren't relevant to Biden's situation

[0] http://cup.columbia.edu/book/mass-pardons-in-america/9780231...

[1] https://www.wlky.com/article/child-rapist-pardoned-gov-matt-...

I imagine there would be some cases where a real hardcore criminal was imprisoned for simple possession because that's the only thing they could get to stick, and releasing such people probably will prove unpopular. However, I estimate the large percentage of people who are convicted only on simple possession aren't hardcore criminals, and thus there may not be any large negative consequence from this. OTOH, Biden runs with the crowd that literally called for abolishing the police a while ago, and succeeded in reducing the police budgets and significantly hindering its function in some major cities. If he's not concerned about that, there's no reason for him to be concerned about the effects of the pardon either.

Biden showed sympathy toward "Defund/Abolish" protesters, but never endorsed their movements. And by virtually every metric, he's increased federal dollars for local police:

Fact check: Political ad saying Biden wants to defund the police is misleading https://www.reuters.com/article/uk-factcheck-misleading-bide...

Biden to request $37B in annual budget to support police and prevent crime: https://thehill.com/blogs/blog-briefing-room/news/3568076-bi...

> I imagine there would be some cases where a real hardcore criminal was imprisoned for simple possession because that's the only thing they could get to stick, and releasing such people probably will prove unpopular.

No matter how popular and light a blanket pardon initiative, political rivals will always blame the president/governor if any of the pardoned do something bad, even if it's a statistical certainty that at least 1/1000 people will get arrested for a crime.

I'm sure the Biden people sussed out the numebrs and tradeoff, e.g. there's not a lot of simple possession convicts, but it's a lot less politically risky to do a bulk pardon for them.

Federal criminal pardons are a plenary power of the executive and aren't judicially reviewable. It's a specific constitutional provision and unlike executive orders.

I think you missed the rest of his actions. The pardon was one part. The other is to review it's classification under the Controlled Substances Act.

You're right, that part is reviewable. (I was only thinking about the pardons).

I don't get it - how does the court get to decide what is a controlled substance and what is not? Shouldn't that be up to some government agency?

It’s up to Congress to make the law. Congress frequently assigns some of that power to agencies, and the courts get to review whether the agencies are following any applicable laws.

It has generally been up the the DEA. When it came time to schedule MDMA it was actually challenged in court by psychologists and psychiatrists along with scientists. The judge recommended a lower scheduling. The DEA said "fuck you" to the judge, petitioners, and the American people and made it schedule 1

https://maps.org/news/bulletin/making-mdma-a-medicine-ii-res...

Just because a pardon can technically be signed quickly and unilaterally doesn't mean that it's pragmatic or wise to do so. As people have pointed out, there's nuances and technicalities, e.g. not applying to undocumented immigrants, that were likely researched and internally debated to limit unforeseen unintended consequences.

And of course, pardons still cost political capital. We all saw how much Biden's people struggled with covid response and getting bills passed -- all of that would be worse if there were fallout from a problematic mass pardon