Islam (and Xtianity) are evil, warped daughter religions of Judaism, as the Rambam writes. But as daughters, they still contain elements of Torah truth.
Capital punishment is still fully on the Torah's statutes books for many sins, both of Jew and Gentile, and even if we haven't got the power to implement, then the Heavenly Court does implement the decree, as was mentioned above. Hence the constant culling everyday of humans in strange unnatural deaths and ways.
The phenomenon of the Muslims demanding Muslim Sharaya Law worldwide, and which has even been accepted by the nominal Xtians in the UK and Sweden, is a warped demented reflection of Torah Halachic Law. "Halacha is the most perfect system for the existence of man in the universe!" (R.Chaim Zimmerman)
But these Muslim shenanigans is in someway preparing the world for when the entire world will literally run according to Halacha! And people won't appreciate it, and most Jews (including Haredim) and non-Jews will not be amenable , which is why most will have to perish, as foretold by the Prophets.
We have to say that in the future, Judaism's Halachic Law, which is also very strict, will be enforced in full, as R.Kahane often stated: "The American Jew is under the impression that Judaism is Democracy, that it is Thomas Jefferson: well it isn't.....!" .
When the Moshiach comes the Jews and Gentiles will not suddenly do teshuva and turn righteous overnight & mitzva observant: it will take months, years and decades.
The commentators refer to bands even of religious Jews who will attempt to assassinate the Moshiach, ergo the Goyim!
During that intermediary period of the Moshiach's early kingship, until "The Righteousness will shine from Jerusalem like a torch", there will have to be very many Halachic executions, some judicial, some extra-judicial.
The question is: who is going to swing the Torah's Hereg sword.......?!