There are many Fannie JPSs. If FNMAT has a face value of $25, then it is over-valued comparing to say FNMAM which has a face value of $50. Anyway, all Fannie and Freddie Commons ad JPSs are substantially under-valued.
If one believe Trump will have 50% chance winning the next presidency, JPSs with face value of $25 should be selling at $12.5 (i.e. 50% x $25) now. It is simple arithmetic. IMO.