Yeah, conventional is the way to go.
Drop some HAARMS do disable their AA and radar systems (we upgraded our HAARMS in 2010 so now they can still destroy a radar site even after it goes "dark" and they hear "MAGNUM!" over the radio and shut off the radar.) Then you send in the bombers and level the shit out of all industrial sites and military interests.
Game Over.
edit: Also, some interesting reading, not sure if you guys are familiar with the demon core story but its pretty fascinating. Apparently, shortly after WW2 ended, Los Alamos was testing the criticality of a plutonium core and not one, but two scientist died fro the same core before it was eventually used in the "able" test bomb. Louis Slotin was the more known of the two who died, and apparently took in 1000 rads of radioactive material when his screwdriver slipped and allowed the berrelyium casing to touch causing the core to go critical. He used his bare hand to knock off the top half of the casing, stopping the reaction and saving the lives of his co-workers. He died a horrible death 9 days later.
Whats sick is when the neutron reflecting casing came together, it actually emitted a blue light (ionizing the air) which lit up the whole room for a moment, and Slotin recounted tasting a bitter taste in his mouth and feeling a burning sensation in his hand after the accident. Nuclear stuff is fucking crazy. Especially the Castle Romeo detonation on Bikini Atoll. Navy crewmen on a nearby vessel said they were actually exposed to fallout directly, saying it looked like snow falling on them.