America and the rest of the NATO alliance didn’t stop spying on Russia when the wall fell. They also didn’t have the massive cuts to R&D, upgrades, and especially payroll in their military personal and equipment suppliers.

I wouldn’t be surprised if the US(or allies) has the complete technical specs of either the S300 or 400 systems. The fact that they designed the current stealth planes with these systems in mind, would make me believe they wouldn’t take the chance of just guessing the systems technical specs.

The theoretical spaced based tracking system has cool potential. They would be just as susceptible to jamming/spoofing as ground based systems, and the amount of data transmission needed for good resolution would be prohibitive. The total infrastructure needed to make them work also seems out of the reach of middle power Russia. I could see China or the US having the money and tech to put one up.

*Even Trump would know that dropping a Nuke would be a step not worth taking. He said he wouldn’t take the option off the table, not that they would be a credible choice in a non-nuclear war. He wouldn’t have a free hand to just launch any in any situation. There’s checks and balances in place to prevent a deranged leader from launching on their own.