A slight win does not equal a mandate. A slight win is just that...slight. It could have gone either way. Right now the Republicans have a small national margin in their favor; if they mess up it WILL shift back the other way just as fast.
At the very least a "mandate" should have a two to one margin, or 66% appoval. The gay marriage ban is what I would consider a mandate in many states....I've heard that in some states it passed with margins of 75% or greater.
J_A_B