1) China, in its overconfidence about being able to survive the scenario, meets with several Saudi, Japanese, and Russian investors to call in 30% of the US national debt on October 23, 1998. We are forced to default on it, by Feburary 1999 faith in the dollar begins to plummet. US government declares that it will not pay Chinese debt until 2010, faith in US government as creditor drops even faster. US dollar begins freefall on June 3, 1999 as President Clinton announces that the debt will be paid by running the printing presses 24/7 until all monies owed are paid. By September food riots break out as money no longer worth paper it's printed on. November sees large scale rioting as farmer co-ops hold out valuable grain stocks in hopes of better market prices but few people have faith in talk of "currency reformation". US announces return to gold standard as only means to solve problem and cuts back 75% of government welfare programs. By December 31, 1999 five cities are burning from riots and ten more are on the verge, martial law is declared and the worldwide economy is suffering in ways that make the Great Depression look like a mild hiccup.
2) Moscow missile command suffers a communications breakdown and misreads a missile test by Norway in 1995, WWIII is accidently invoked
3) As #2 but with Lt col Petrov calling in sick in Sept 1983 and a computer glitch results in WWIII