“If they can do it in Moscow, what will stop them from doing something similar on U.S. soil?”
Nowhere near comparable. Russia is Ukraine’s enemy; the US is for all intents and purposes Ukraine’s ally.
“Nowhere near comparable”
That’s an assertion, nothing more.
If Ukraine is fully defeated, all of these assassins will end up living in the USA or EU
More like Ukraine’s Sugar Daddy.
Probably so, though India secret services recently tried to assassinate Sikh separatists in both Canada and the USA, and the Mossad wouldn’t hesitate to kill Hamas leaders who sneaked across our porous border.