is required to suspend it. That would/should be laid out in your organization's bylaws, which are separate from Roberts Rules. There can be different types(percentages) of "majorities" required. Bottom line: no one can answer this definitively without reading the organization's by-laws in para materia (Latin for "in conjunction with") with Roberts Rules, or whatever parliamentary authority the bylaws have incorporated by reference. There are at least three possible such authorities: Roberts, Demeter's or The Standard Code of Parliamentary Procedure.
On edit: You do know, I hope, that Roberts Rules or any other code of parliamentary procedure do NOT apply to your organization unless said rules have been specifically incorporated into your organization's by-laws.
From Wikipedia:
http://en.wikipedia.org/wiki/Suspension_of_the_rules"When not permitted
Rules which embody fundamental principles of parliamentary law and rules protecting absentees or a basic right of the individual cannot be suspended, even by unanimous vote.<3><4> Thus, it would be illegal to suspend the rules to allow non-members to vote; to authorize absentee or cumulative voting; to waive the requirement of a quorum; or to waive the requirement for previous notice for a bylaws amendment. Moreover, the rules cannot be suspended to take away a particular member's right to attend meetings, make motions, speak in debate, and vote; these can only be curtailed through disciplinary procedures.<3>
Three of the major parliamentary authorities - Robert's Rules of Order Newly Revised, The Standard Code of Parliamentary Procedure, and Demeter's Manual - agree that provisions in the bylaws that do not relate to parliamentary procedure may not be suspended.<4><5> Demeter notes how this plays into the reality of parliamentary situations:<6>
“ Bylaws cannot be suspended even by unanimous vote. But sometimes circumstances, expediency or strong assembly determination in behalf of a cause or proposition make violations necessary. In all such cases of violations, the action taken is illegal per se; but if no one objects at the time, or never challenges it at any time thereafter, a violation never challenged is never a violation. ”
Similarly, Mason states:<7>
“ It has been held that public bodies can adopt rules, even by majority vote, that cannot be suspended or amended without a two-thirds vote, but it is also held by the courts that actions, taken in violation of procedural rules of parliamentary law and of adopted rules, are valid nevertheless, since failure to conform to the rules of this class suspended them by implication. ”
The action is still illegal if it violated a mandatory constitutional provision, since a legislature cannot suspend the constitution.<8>