If I were completely cynical and amoral I'd use Ukraine as a quagmire trap. Take direct intervention off the table, beef up the defences enough to cause a probl

If I were completely cynical and amoral I'd use Ukraine as a quagmire trap. Take direct intervention off the table, beef up the defences enough to cause a problem, and wait for the Russians to take the bait. Then when Russia is trapped in a continuing guerilla war which is generating huge economic consequences and negative PR at home and abroad, wait for the regime change in Russia to happen spontaneously. It's a risky strategy given nukes, but not entirely unimaginable as realpolitik.