What if Russia Launched an Attack on USA?

It's a question that's been on the minds of many, and with the War in Ukraine and US-Russia relations at an all-time low, it's a possibility that's hard to ignore.

One thing's for sure, Putin is not happy about the West repeatedly coming to Ukraine’s aid in the Russo-Ukrainian war and with Russia’s army failing miserably on the battlefield, it may only be a matter of time before Putin’s threats to either back off and stop helping Ukraine or face a showdown start coming in. 

What could a Russian attack on US assets look like? Is the possibility of a nuclear war a real concern? And what would be the global implications of a war between Russia and the US?