I am not saying that you guys are wrong, but I have a different opinion. I think you must work with what you have where you are. Don't wait! Some people cannot pay for lawyer's fees, therefore they just wait until they can put some money aside. And like JoeF said, many lawyers seem to be representing USCIS interests in reality. They sit there and argue with you on how and why you should keep waiting and waiting and waiting...
Anyway, if you make a quick search online, you will find that a couple of people have filed for a mandamus in 2004 successfully. They did it PRO SE. Also I know of case filed in Boston Pro SE which was also successful (03-12246). All these cases did not go to trial.
You are absolutely right when you say you must have a knowledge of the law when pursuing this route, but you will find the court system very helpful in explaining the rules and ways that you should follow and proceed with. Of course they will not give you legal advice, but they have Guides for Pro Se applicants, and the judges are usually tolerable for any mistakes made in writing. But you MUST, i repeat, you MUST understand and know the codes and regulations applying to your case. Also you need to know what you are asking for and make sure you base your demands on the applicable laws.
As a strategy, I think if they have time and the desire to fight for their case and to learn federal laws, applicants may petiton the courts Pro Se, then if things get messy, and they think their case may go to trial, they can hire a lawyer to help them. Otherwise, if they know how to write and research, their case may be resolved within three months of their petition.
Good luck.
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