A writ of mandamus is a lawsuit brought in Federal Court against a government agency to compel them to act on something to which the plaintiff has a right. At our firm we have brought writs of mandamus against the U.S. State Department, the Department of Justice, and USCIS in relation to our client's immigration cases to compel the government to act.
As an example, we have had clients with long-pending adjustment of status cases – cases that were pending much longer than normal and with no information from USCIS as to why or any indication that they were acting on the case at all. In these and similar instances we were able to file a lawsuit against USCIS alleging that they were delaying the decision of the case unreasonably.
The results in these cases are usually favorable. Although in filing a writ of mandamus you are not asking a judge to decide your case, merely force USCIS to issue a decision. There is no guarantee as to what that decision will be.
These cases are complicated and there is no black and white timeline for as to when a writ of mandamus should be filed or will be successful. However, if you feel your case has been delayed unreasonably you should consult with an experienced immigration attorney who can better advise you with the specifics of your case in mind.