Completely impractical.<p>ICBMs can&#x27;t even reach orbit, never mind Mars.  So we&#x27;d have to build enough rockets to lift around 10,000 nuclear warheads to Mars, typically weighing around 300kg each.<p>The inevitable launch failures would be interesting too.  Even if 99% reliable, that&#x27;s still a hundred nuclear warheads raining randomly back to Earth.<p>And on top of all that, I don&#x27;t think it&#x27;d actually make Mars significantly warmer.