User blog comment:Green light ops/Battlefield 4 Campaign Details Reveal/@comment-4563909-20130719065155/@comment-11410452-20130719210229

@PLR: Not technically. The Sino-American War of BF2 included little tidbits which allude to certain reasons as to why the war happened, most likely due to some sort of peak oil crisis, since a good number of maps revolve around oilfields or the strategic control of them if one side should emerge victorious.

However, BC1 and BC2 never went into any details as to why the Russians and Americans went to war. It's just a generic "the Russians are the bad guys, trying to take over the world and it's America's job to stop them and spread democracy all around" scenario. No hints, no incognito clues of any kind. And the MEC were pretty much just thrown into the mix for shits and giggles.

Now BF3 did state a clear-cut reason as to why the War of 2014 broke out, and anyone who played through the entire campaign and payed attention to every bit of dialogue would know it. Being a sequel to BF3, it can be assumed (although not confirmed) that the conflict between the Russians and Americans extended for the next six years into the events of BF4. (Unless for some reason, ANOTHER Russo-American conflict emerged unbeknownst to public knowledge.)