General Events of the Timeline
(taken from Uncanny X-Men #141, Excalibur #66)
Senator Robert Kelly, who preaches anti-mutant views, is killed by Mystique‘s Brotherhood.
Another rabid anti-mutant politician is elected president.
The first “Mutant Control Act“ is passed by the Supreme Court, because they considered it unconstitional.
The Sentinels program has been reactivated.
The “Mutant Control Act“ is accepted, mutants are stripped of their rights.
“Genetic Purity Act“
Content unknown, probably regulates breeding. Citizens were divided into three different groups, H are the baseline human, A are normal people with genetic potential for mutation and as such forbidden to produce offspring. The mutants M had no rights anyway.
By now the Sentinels have taken over the USA and most super-beings, mutant or not, have been killed or incarcerated.
Kate Pryde is arrested among other X-Men. One month later she is found guilty of various acts of terrorism and violating the “Genetic Purity Act“ , her punishment is life sentence in the South Bronx Mutant Internment Center.
The X-Men break out of the camp and try to alter the timeline by sending Kate to the past. The mission fails, only Kate and Rachel survive. They try to destroy the Nimrod base, and Rachel is transported to the mainstream Marvel Universe.
Rachel and her teammates Excalibur return to the future and help some local hero team to change the Sentinels Prime Directive.