I don’t think Iran is a proxy for Russia. Sure, Russia will use them, as in drone purchases, but trust them with a nuke? With the muslim record of insurgency in various Russian republics? Too risky, IMO. Likewise Pakistan and China. Also, all nukes leave fingerprints; if Tehran dropped a Chinese bomb (or an Iranian bomb with Chinese uranium) everyone would know.
Yeah, the US is in decline like all empires. They just don’t last like they used to. But I can’t see Israel taking over. What is most likely now, IMO, is Russia filling the moral, financial, industrial and political vacuums developing in Europe. The continent is gutting itself slowly and irrevocably. Russia won’t invade in a conventional sense, vacuums suck, and Russia has the energy and other raw materials that its oligarchal structure can use externally in weak countries. Maybe a Hungaro-Russian alliance, with Slovakia and possibly Poland (yes, solidly Christian, anti-immigration, fiscally sound – Russia is a better match in the next round of alliances than western Europe) resisting the muslim hordes and economic collapse.
America would still have a chance if Trump would, as you say, stick to his promises. A bit late now, I suppose, and always a risk that the Dems will steal the next elections if SAVE doesn’t get implemented properly. That’s the trouble with foreign wars, they distract you from what’s happening at home.
