I got the idea of doing this from the Slate Star Codex blog. Anatoly Karlin made some predictions in this style as well. I hope more bloggers do this. The little graph that Scott Alexander put at the end of this post is so simple and useful that it's a shame that I didn't think of it myself.
For the world's sake I hope I'm being too pessimistic with some of these predictions:
Hillary will not be prevented from appearing on the ballot in November by legal trouble stemming from her e-mail scandal or from anything else: 100%.
At a high enough level everything is political. It doesn't matter what she did with those e-mails. What matters is that the power structure strongly prefers her to Trump. It also prefers her to Cruz. So they're not going to let her be sidetracked.
Similarly, I'm sure that Nixon was forced to resign because the power structure hated his policies, not because of anything to do with Watergate. Kennedy was widely believed to have cheated in the 1960 election. I'm assuming that both sides cheated during the 2000 recount. But it didn't matter. At that level illegality is only a pretext. Politics and policies are everything.
Hillary will be the Democratic nominee in 2016: 99%.
Bernie was never going to win and Hillary is a very healthy person for her age.
Trump will be the GOP nominee in 2016: 80%.
Trump will not be assassinated or severely disabled by an assassination attempt before the end of 2016: 85%.
I sketched out this post in my mind yesterday, before today's attempted attack on Trump, and this item was already there.
Hillary will win the 2016 general election: 70%.
The number of illegal aliens in the US will not decline by more than a quarter during the 2017-2021 presidential term: 95%.
I think that the likelihood of Trump becoming president is quite a bit higher than 5%, but the likelihood of him winning, attempting to honor his promises and actually succeeding at it is pretty low.
More than 5,000 US soldiers and military contractors will be killed in action during the 2017-2021 presidential term: 80%.
I suspect that the Obama administration will be remembered as a window of relative peace. The fun that many had over Obama being awarded the Nobel Peace Prize will probably seem idiotic to future generations.
No part of Syria will be controlled by any member of the Assad family by 1/20/2021: 90%.
At least one town or city with a pre-war population of more than 10,000 will change hands in the Ukraine-Novorossiya conflict before 1/20/2021: 70%.
Kharkov, Odessa and Donetsk will not change hands before 1/20/2021: 90%.
The Armenia-Azerbaijan conflict will again erupt into open warfare with more than 1,000 dead before 1/20/2021: 50%.
The UK will not leave the EU as a result of the 2016 referendum: 95%.
It's my impression that the EU is non-negotiable to the Euro powers that be. So even if Brits vote for leaving, it's hard for me to imagine them actually leaving. The results of the referendum could simply be ignored.
The Front National candidate will not win the French presidency in 2017: 95%.