The Constitution is already pushed beyond all reason for poor people anyway. You might have a "right" to a public defender, but good luck getting them to spend much more than 10 minutes on your case. (https://www.mprnews.org/story/2010/11/29/public-defenders) They're so overworked that it can be impossible for them to spend more than a tiny fraction of the time they actually need to do their job (https://www.kansascity.com/news/local/crime/article237036919...).
In the same way you have a "right" to speedy trial, but unless you're rich you can spend years (or even a decade) waiting behind bars (https://www.thecity.nyc/2022/8/17/23310771/why-some-spend-ye...).
It seems like we've already decided that if you can't pay the court fees you aren't entitled to access to our "justice" system (https://digitalcommons.law.seattleu.edu/sulr/vol44/iss3/11/)
I don't think it's too far fetched to imagine the courts telling poor people they have to settle for an AI to represent them unless they can fork over the money to hire one themselves.
If an AI is just as capable (if not more capable) than a real lawyer, we'll be seeing rich people and corporations using them instead of humans. Until we see that, I'll assume that if poor people are forced (by law or finances) to use them they'll be getting the short end of the stick.
Public defenders would be more effective if they didn't have to talk to their clients?
For a natural text generation/chat system like ChatGPT, at the moment this is effectively impossible and frankly I don't see it being sufficiently fixed for something as complex as teaching law to a non-law-student any time in the near future.
It's not like a "jailhouse lawyer" will do any better. Though it might cost something you didn't expect, such as a new witness against you or a shower pal.