I strongly disagree with the assessment on Russia. Russia has been a threat to world wide stability since the Bolshevik Revolution put the communists in power in 1923. They were co-aggressors with Germany at the start of WW II when they parceled out the Eastern European nations between them. Churchill in fact warned the US about Stalin's aggressions even before WW II ended, but he was voted out of office and FDR died before anything could be done (though it is doubtful FDR would have done anything). Since then they've been actively supporting communism throughout the globe - from supporting Mao in China's bloody civil war to Castro's regime in Cuba (and the threat of nuclear missiles in Cuba) to various other forms. Yes, they took a hit under Gorbachev because Reagan basically spent them under the table in the arms race, but militarily, they are second only to the US in overall firepower. They are still the only nation with a true long range bomber force and have far more ICBM's than any other nation save the US. They have an active navy - again second only to the US - with very capable attack and nuclear missile submarines.

Do they have their weaknesses? Certainly. Their governmental structure supports a black market instead of free markets which decreases tax revenue. They openly suppress and control the media. They are largely dependent on oil revenue. And they like to throw around their military weight in neighboring countries like the Ukraine and now Syria. Have they to some degree been overshadowed by the Chinese and the North Koreans in political circles? Sure. But I think Russia is far from a paper tiger.

The Soviet Union of AR's day knew that nuking the USA would be suicide due to a near simultaneous retaliatory strike.
This is why the USSR backed off from the Cuban Crisis that me dino and friends sweated though as kids. Those "duck and cover" Civil Defense films were scary back then.
Methinks Rocket Man came to realize that North Korea is by far a smaller target than Russia that the USA can obliterate with pinpoint accuracy with a lot more nukes.