Speaking of vastly unrealistic ... Medicare for all. My rough as sandpaper take on the odds, assuming Warren (or Sanders) wins the nomination:
Warren/Sanders defeats Trump: 50%
Senate barely swings to Dems: 10%
Senate gets rid of filibuster rule: 33%
Senators Tester and Manchin vote for the measure: 10%
Equals .16%
Sorry for bringing up a month old post but I've been away on "vacation" and couldn't get here sooner. acbytesla said that numbers don't work that way, you said they pretty much do, and the truth is somewhere in the middle due to the ambiguity of the numbers you're using. Probabilities don't just multiply together like that unless they are
independent (the probability of one happening does not affect the probability of the other). Let me give you a simple example:
Take a fair, six sided die. Paint "Heads" on all the even numbered sides, "Tails" on all the odds. What's the probability of rolling a Three and a Tails in the same roll?
Probability of a Three: 1/6
Probability of a Tails: 1/2
Multiplying these gives 1/12, which is obviously wrong because rolling a three guarantees you roll a tail.
The probability of multiple events does multiply, but in general you can't just multiply the original probabilities. This is how it works:
Probability of A and B = (Probability of A) times (Probability of B
given that A already happened)
In our example:
Probability of a Three: 1/6
Probability of a Tails, given that a Three was rolled: 1
1/6 * 1 = 1/6
Anyway, the numbers you've presented are ambiguous: In your list, are you giving the individual probabilities for each, or is each already conditioned on all previous items in the list? If it's the former, it's wrong. If the latter, it's correct, but since the numbers were made up anyway it's rather meaningless.