Stop picking fights with all the other countries. Take climate change seriously. Maybe then you can survive long enough to build things on Mars.
However the Soviets crashed several RORSAT reactors actually on earth, which is indeed much worse (and many cores are still up there in parking orbits)
But in any case, these are all problems that are both less likely with new designs (e.g. kilopower uses sealed heat pipes with no moving parts for coolant), and less of a concern when the reactors are either in interplanetary/cislunar space or are nice and buried.
/s
They also did not recently create “space force” to militarize space and pander for votes in the most obnoxious way possible.
Hasn't the US been using Russian facilities and rockets to go to the (jointy built with Russia and others) ISS for the past decades? That seems collaborative to me...