More: Language requiring healthcare professionals to care for veterans regardless of their politics and marital status has been explicitly eliminated.

Doctors and other medical staff can also be barred from working at VA hospitals based on their marital status, political party affiliation or union activity, documents reviewed by the Guardian show. The changes also affect chiropractors, certified nurse practitioners, optometrists, podiatrists, licensed clinical social workers and speech therapists.

In making the changes, VA officials cite the president's 30 January executive order titled "Defending Women from Gender Ideology Extremism and Restoring Biological Truth to the Federal Government". The primary purpose of the executive order was to strip most government protections from transgender people. The VA has since ceased providing most gender-affirming care and forbidden a long list of words, including "gender affirming" and "transgender", from clinical settings.

Medical experts said the implications of rule changes uncovered by the Guardian could be far-reaching.

They "seem to open the door to discrimination on the basis of anything that is not legally protected", said Dr Kenneth Kizer, the VA's top healthcare official during the Clinton administration. He said the changes open up the possibility that doctors could refuse to treat veterans based on their "reason for seeking care " including allegations of rape and sexual assault " current or past political party affiliation or political activity, and personal behavior such as alcohol or marijuana use".