A relatively recent large-scale case from the U.S. that comes to mind is the internment of Japanese-Americans. I'm not sure if I can point to a specific Constitutional amendment that it violated (4th amendment on seizing a
person without probable cause? Probably 9th amendment, that there are are additional rights not enumerated), but I think most declarations of rights cover a right to liberty unless one is charged with a crime or other strictly limited exceptions, and it seems clear that the Japanese internment violated that.
Interestingly enough, the Supreme Court of the time seems to have upheld part of what was done to the Japanese-Americans[1]. "In effect, the two rulings held that, while the eviction of American citizens in the name of military necessity was legal, the subsequent incarceration was not"[2]. About the first ruling, Wiki says: "Chief Justice John Roberts explicitly repudiated the Korematsu decision in his majority opinion in the 2018 case of Trump v. Hawaii. The case is often cited as one of the worst Supreme Court decisions of all time."
We haven't gotten as far as large-scale violations in the U.S. of a right to not be killed by official government policy (death penalty notwithstanding). (Also notwithstanding the FDA delaying the introduction of lifesaving drugs.) It has certainly happened in other countries, though. In the small scale, the U.S. government does sometimes assassinate individuals, and seems not too squeamish about killing whoever else is in the blast radius (some may protest that those people aren't citizens). I would admit it's pretty unlikely they'll go that far on this particular right (in the absence of a revolution), but for the majority of rights, it seems there will be circumstances where politicians will plead "emergency" as a reason to violate them, and often enough will get their way.
[1] https://en.wikipedia.org/wiki/Korematsu_v._United_States
[2] https://en.wikipedia.org/wiki/Internment_of_Japanese_America...