to marali
You cannot use 1447b. You can use general mandamus statute 28 USC 1361 and Administrative procedure act, 5 USC 555(b) and 5 USC 706. 5 usc 555(b) states that a federal agency should perform its duty within reasonable time. 5 usc 706(1) says: "The reviewing court shall compel agency action unlawfully withheld or unreasonably delayed;". So you need to prove that the USCIS unreasonably delayed adjudication of your N400. Now, while the passage of time does not guarantee that the court will recognize the delay as unreasonable, the general rule is to wait 2 years before filing a mandamus suit. It does not mean you cannot do it now, but the chances to prevail are low.
You cannot use 1447b. You can use general mandamus statute 28 USC 1361 and Administrative procedure act, 5 USC 555(b) and 5 USC 706. 5 usc 555(b) states that a federal agency should perform its duty within reasonable time. 5 usc 706(1) says: "The reviewing court shall compel agency action unlawfully withheld or unreasonably delayed;". So you need to prove that the USCIS unreasonably delayed adjudication of your N400. Now, while the passage of time does not guarantee that the court will recognize the delay as unreasonable, the general rule is to wait 2 years before filing a mandamus suit. It does not mean you cannot do it now, but the chances to prevail are low.