Non sequitur

A set of statements leads to conclusion X. Yet conclusion Y is drawn.

An argument is given from which a perfectly valid and sound conclusion may be drawn, yet the stated conclusion is something else.

Examples:

1. There has been an increase in burglary in the area. It must be because there are more people moving into the area.
2. The Chief Executive has a Law degree. We'd better make sure we're all above board.
3. You are hot and I am cold. You are wearing a brown coat. So let's go for a drink.

Sometimes this fallacy is used by people who want to prove something but do not know how, so they use any argument and then tack their desired conclusion on to the end. This is something that politicians often do.

This is effective persuasion when the listener does not work through the logic of the argument and is persuaded simply by the fact that some kind of argument is being used (as opposed to the conclusion being given as a simple statement). This can be encouraged by speaking with passion and apparent authority.