The Second Cold War was a state of political and military tension after the Ukraine Crisis between the Western Powers (the United States, its NATO allies and others) and the Eastern Powers (the Union State and its allies in the Eurasian Union).
The Second Cold War officially began in 2018 when American President Hillary Clinton in a historic speech to the country famously said that "A second cold war has dawned upon the Earth." Like the first Cold War, it was deemed "cold" because the two superpowers never engaged each other directly during this period, although there were major regional wars in Europe, Asia and Africa that the two sides supported. The Cold War split the temporary alliance against global terrorism, leaving the Russian Federation and the US as two superpowers with profound goals: the former wanting to expand its influence across the Eurasian Continent (known as the "Eurasian Dream"), and the latter wanting to halt Russian influence and continue its global hegemony. A non-aligned movement reemerged, led by rising superpowers such as Mexico and later Canada. Much like the previous cold war, the two superpowers never engaged directly in full-scale armed combat but they each armed heavily in preparation of a possible all-out nuclear world war. Each side had a nuclear deterrent that deterred an attack by the other side, on the basis that such an attack would lead to total destruction of the attacker: the doctrine of mutually assured destruction or M.A.D. Aside from the development of the two sides' nuclear arsenals, and deployment of conventional military forces, the struggle for dominance was expressed via proxy wars around the globe, psychological warfare, propaganda and espionage, and technological competitions such as the Scramble for Space.
The first phase of the Second Cold War began almost immediately after the end of the Ukrainian Civil War in 2017. Russia integrated and expanded the Union State even further by creating a de facto confederation of pro-Russian states while the United States attempted a strategy of global containment to challenge Russian power, extending military and financial aid to European countries (for example, supporting the pro-Western side in the Moldovan Civil War) and attempting to maintain the NATO alliance. The United States however, proved that no matter how bad a regime is, as long as it is anti-Russia, it is good enough for them (such as the P.R.I. in Italy or the Golden Dawn in Greece).
Another thing that worried the United States was Chinese expansion. China, early on anyway, was the unofficial third belligerent in the Second Cold War. Though it had been an ally of the Union State, it would often double-cross Russia to benefit their own cause, as shown with the Chinese-backed coup d'etat against the Russian-backed regime in Turkmenistan. Chinese expansionism was also the official justification for the United States' hegemonic grip over the Pacific, however the unofficial justification was to preserve American influence over East Asia, not wanting to suffer another "European Fiasco".