O.K. here is my take on that....
First and foremost there needs to be a definition of a quorum. Our by-laws specifically spell out what a quorum is and how or when a meetingh can be held. We have to inform the membership of a meeting 5 days prior in order for the meeting to take place. A quorum in our club By-Laws is defined as 12 members minus the executive board. So under both these circumstances if these two items are not filled no vote is legal. EXCEPT an executive order, which can only be done in lieu of a meeting or in an abscence of a quorum only to be held long enough for the membership to vote it up or down.. Example, paying the port-o-poty. I can issue an executiove order to have it paid if I am missing a quorum, but at the next meeting the membership can determine they do not want to pay it or that they do. I can only issue executive orders in times of emergency, no quorum, or if it is deemed by a vote of the executive board to be in the clubs best interest pending a membership vote.
Here is where it gets tricky. Robert's rules ONLY fill in where the By laws end. In other words Robert rules do NOT supercede By-LAws, but makes up for their abscence. If your By Laws do not specificallyh define a quorum that Robert's rules can in this case.