Police and firefighters are exempt from right to work due to special collective-bargaining rights that prevent strikes.
It does not exempt American citizens from the list of "nations, organizations, or persons" against whom the war is to be waged.
If Congress wants to exempt itself from the Obamacare exchanges, it should go ahead and offer the same relief to everyone else.
late 14c., from Old French exempt (13c.) and directly from Latin exemptus, past participle of eximere "remove, take out, take away; free, release, deliver, make an exception of," from ex- "out" (see ex-) + emere "buy," originally "take," from PIE root *em- "to take, distribute" (cf. Latin sumere "to take, obtain, buy," Old Church Slavonic imo "to take," Lithuanian imui, Sanskrit yamati "holds, subdues"). For sense shift from "take" to "buy," compare Old English sellan "to give," source of Modern English sell "to give in exchange for money;" Hebrew laqah "he bought," originally "he took;" and colloquial English I'll take it for "I'll buy it."
mid-15c., from Middle French exempter, from exempt (adj.); see exempt (adj.). Related: Exempted; exempting.