A logical fallacy
in which a threat
is made instead of a logical argument
to support the conclusion
Example: "If you don't agree that I'm right, then you're fired" doesn't prove he's right.
To prove use of Appeal to Force, identify the threat and show that is has no relation to the truth of the proposition.
Don't confuse this with a proof that Bad Things will happen, but see also Slippery Slope.