If it can be proven that she deliberately escorted the person through the non-public exit to the courtroom with the intent of helping them evade arrest by officers with a warrant who were waiting outside at the other entrance, how would that not be an arrestable offence?
We're extremely light on facts right now, so I'm not taking the above quoted story at face value, but if one were to take it at face value it seems pretty clear cut.
The part that makes it not so clear cut is that this is really a constitutional issue rather than a criminal one. It is not credible that the judge was trying to ensure the man could keep living in the US undocumented. She was defending her court. From a judge's POV, arresting a plantiff/defendant in the middle of a trial is a violation of their right to a trial and impedes local prosecutors' abilities to seek justice.
Ultimately this seems like Trump asserting that the federal executive branch has unfettered veto authority over local judicial branches. That doesn't sit well with me.
The charges against her are not about her behavior during her court, they're about what happened once the court was adjourned and the defendant was starting to leave. She successfully defended the process within her own courtroom and it's alleged that she went a step further in securing the defendant from their impending arrest on an unrelated charge.
There's definitely a conversation to be had about whether people should be safe from immigration law enforcement while within a courthouse, but at the moment as I understand it that is not a protection that exists.
It doesn't matter if court was adjourned, she was still at work and performing her official duties. In particular she asked the ICE agents if they had a judicial warrant and was told no, it was administrative. A federal judicial warrant clearly outranks a local judge and it would be fine to arrest her if she defied it. It is not clear that an order from the executive branch does the same. That doesn't mean local judges are immune from federal prosecution (e.g. corruption charges if someone takes money to rule favorably), but there is a fairly high bar, I don't think her behavior even comes close to probable cause for obstruction of justice or shielding an undocumented immigrant.
The reason every other administration besides Trump refused to go into local courthouses to deport people wasn't about "whether people should be safe from immigration enforcement," it was about separation of powers.
I guess I would hope it takes more then that to rise to the level of obstruction.
Additionally, you have to prove intent, and unless the judge was careless, I doubt they will ever be able to do that. I'd bet the prosecution knows this, I don't think they expect the charges to stick. It seems this arrest was done to send a message.
More evidence of that is that typically in this kind of case they would invite her to show up somewhere to accept process, not be arrested like a common criminal.
We're extremely light on facts right now, so I'm not taking the above quoted story at face value, but if one were to take it at face value it seems pretty clear cut.