The US should start a nuclear war with Russia. Mutually assured destruction sounds fine with me.
(guesstimating follows)
~3/4 people would survive the first few hours
~1/10 people would survive the first week
~1/25 people would survive the first month
~1/100 people would survive the first 2 months
~1/5,000 people would survive the first year
Guessing that about 2 million people (out of currently 8 billion) would survive the nuclear winter and famine/other environmental impacts*. I doubt that you'll be one of those lucky .025% that survive; likewise for all the other people on this forum**. (p_p definitely wouldn't survive, based on his current post count of 8
666.

)
And don't anyone try to get out of it with "I live there so I won't be affected." It only takes about 100 nuclear bombs to cause a global nuclear winter, which pales in comparison to the amount possessed by the US and Russia alone, not even counting their allies. And that nuclear winter is the real killer. So you might live a little longer, but you're still doomed to an arguably worse fate.
*And that's probably a low estimate for the death toll.
**Correction: I ran the numbers, and about 6.7 people who have ever had an account on this forum would survive, on average. Assuming none of them have already died, which is obviously a false assumption.