It has been long since a world war was engulfed upon humanity. Back then, it all used to be so futile. Everybody was sacrificing their lives for their friends, for their neighbours, for their city, their nation. For an ideology... It was the deadliest conflict of them all, and nobody thought anything similar would come back ever again. Boy, how wrong they were. Even though a period of peace existed, The Golden Century (1950s - 2050s) brought with it an unforseeable turn of events.
Every man and woman wasn't pleased with just having fresh water coming out of the wall in sinks, or radios meant to inform the average person of hot, spicy news about Elvis Presley. No, they wanted more. Always more. They wanted robots to do their work for them, and electronic computers to do their thinking for them. But nobody thought what the aftermath of this lust for "more and more" would be. The resources used to make the world's fancy gadgetry were dwindling, and so was the patience of every nation.
Early on in the 2050s, the European Commonwealth, proud of the fact that it had finally unified Europe after a millenium of fighting, invaded the Middle Eastern Federation in response to the latter's continuously rising oil prices. The war that resulted shook the world to its core; one of the last hotspots of crude oil in the world, the Arabian Peninsula, was effectively dried up of it, as the last drops of oil were used to fuel the Federation's military, while Europe did so too. The war and subsequent atomic bombings of several Middle Eastern cities turned most of the Middle East into a lawless zone, save for its Southern part (which became two puppet states of the USA and China, respectively), and American-supported Israel. Europe didn't remain civilised for much longer too, but it did manage to built several bunkers designed for the protection of the population, in the event of a "nuclear" civil war (they were much more poorly equipped than Vault-Tec's marvels; the continent wasn't really ravaged by atomic fire anyway). About a year afterwards, the Commonwealth did end up in a long and bloody civil war.
This, however, was just one chapter of the Resource Wars. In 2055, China's biggest allies: the Soviet Union, the People's Republic of India, the Socialist Federation of South America (basically Greater Brazil) walked out on its partner nation in the Sino-Soviet Split. The United States of America was hit hard by the New Plague, which, unbeknownst to America, was a Chinese biological weapon which ended up in the hands of a well-placed high-ranking American corporate leader. The USA closed its borders, but not without invading Northern Mexico first.
But this didn't stop the two superpowers. America began to become more and more of a police state, silently wiping out the "Communist threat" (think anyone who the President or other high-ranking members of the Federal Government hated). Most of the leading corporations of that time became more and more immersed in secret projects with the Pentagon, including the Forced Evolutionary Virus, which at first would have been used to create the "American super-soldier", but as research on it continued, the US Army's plans for it were as a biological weapon to be used against the Chinese in case of a war. Suffice it to say that the FEV was used on actual, living humans with catastrophic results (here's what the "Communist threats" are used for).
China went on a rampage, invading its neighbouring nations. Mongolia, Laos, Cambodia and Myanmar fell in weeks, but the Chinese invasion of Vietnam caused trouble. US spies in Beijing intercepted plans for this "liberation" early, and mobilised quickly enough in order to make South Vietnam secede from the actual Vietnam. South Vietnam was essentially a puppet state, but it was equipped with cutting-edge tech, provided by the US. After two years of fighting (2061 - 2063), China finally annexed Vietnam, but at a high price. Not bothering with a similar risk, China instead opted to instate puppet governments in Thailand and Indonesia (before you ask, Malaysia and South Borneo were invaded by the US during the Vietnam War). But besides a high death toll, the Vietnam War created another monster. Australia, scared of a Chinese invasion, called to its long-time ally South Africa for help. The New Commonwealth ensued. The nuclear-powered S. African and Australian Armies turned out to be more powerful than ever expected. The New Commonwealth's invasion of Indonesia proved the world that, despite not as technologically advanced as China and the US, other parts of the world still packed quite a punch.
In the three years that ensued, China and the US created as much satellite countries as they could. This led to regional, small wars between these states. Northern Africa was consumed by the flames of war so bad, that all governments in the region collapsed, and the area became lawless, just as the Arabian Peninsula awhile back. The European Civil War wasn't the target of proxy wars, though. Throughout the rest of the world, it became known as No Man's Land. Italy, along with its allies France and Spain, were in a constant state of battle with the UK and its allies. Similarly, Hungary, along with Bulgaria and Romania waged war on Greece and Yugoslavia. The Soviet "intervention" in Czeckoslovakia transformed into an all-out annexation, as the populace of Czeckoslovakia was begging the USSR to "accept them". The United States' forceful annexation of Canada is a foremost example of the aggresive race for territory that has been going on.
What nobody realised is that by fighting, everybody loses something. As oil begins to disappear forever, desperate people who are aware of this problem strive to solve it. Atomic-powered cars (expensive, nevertheless) have been, at last, invented, but it is too little, too late. The Societal Preservation Program, or Project: Homeland has been started by the American corporation Vault-Tec and the Pentagon, in order to "save" the population of the US from a potential nuclear apocalypse. But the average Joe doesn't know the true, sinister purpose of the Vaults: the study of pre-selected segments of the population in case of isolation from the rest of the world. Gruesome, yet intentional, design flaws have been projected on most of the 150 Vaults that exist throughout the US and newly-annexed Canada, as a result of the American Federal Government's convinced belief that total war is bound to happen once more, and that it's certain that the nature of man will destroy an average man, forever, clutching onto the desperate idea that perhaps they (and only they) can survive.
The last place where oil exists above ground anymore on Earth is Alaska, but while America is thriving on its last civilised years, China grows restless across the Pacific Ocean. Not so "Pacific" now, is it?