回复：今天最后贡献一次，整理小白兔关于mandamus的回答

The XBT’s response to mandamus is generally correct. But let me supplement the response to Q#1. Some attorneys refuse to accept out of district case not simply because it’s time consuming. He or she will take the case if the client is willing to pay additional fee to cover the time. The other reason is that the attorney may not be admitted to practice law in that particular federal district court. The attorney has to apply for admission or file a pro hac vice motion in that federal district court. He or she may not be familiar with the local federal district court rules and operating procedures which are somewhat different from district to district.
Contrarily, once an attorney is admitted to practice in any state, he or she can practice immigration law anywhere in the country except for the federal court practice.