If people from nations that do not have capital punishment don’t think their citizens who come here and commit crimes punishable by capital punishment should NOT fall under our capital punishment laws, then they have a very simple remedy - don’t come here to begin with. Otherwise, it is mere nationalistic arrogance for them to think OUR standards of punishment must conform to theirs.
We should do Mexico one more favor; ban all travel to the U.S. by Mexican nationals until Mexico signs a treaty acknowledging that its citizens on our soil ARE subject to whatever standards of criminal justice OUR laws employ, whether they agree with them or not.
Can we expand that to include a signed acknowledgement by people who immigrate here from Islamist nations, or better yet, all nations, saying that they realize we are governed by the federal Constitution and the constitutions of the individual 50 states, and that they will not promote or support the institution of Sharia law in the United States of America? Sounds crazy, I know.