Immigration Court Subpoenas Are Possible

Not only are subpoenas for documents possible, but if they are needed to obtain documents essential to the case, an immigration judge's refusal to issue the subpoena can be a way to overturn the decision. See, for example, Kaur v. INS, No. 99-70395 (9th Cir. Jan. 24, 2001)!

The key is to explain what you expect the document will show, why the document is essential to the case, and that there is no other way to obtain the document. One way a document can be essential is that it would be used to impeach the credibility of a key witness.