popa: they do NOT have to conform to our standards, however when it comes to the possibility of jewish lives being taken we do indeed have to worry. therefore when it comes to supporting the death penalty we do have to take a stand that is in accordance with halacha. martin grossman would not have been killed if there was no death penalty, and it is the people of a nation that decide such things.
as for jail sentences, no they are not desirable but we do have to be realistic, we are in galus and can not impose our justice system on the world. when it comes to jail which is not necessarily pikuach nefesh per se i would accept that as a lesser evil than the death penalty.