This memorandum binds only this Senate - the 109th. If the Democrats play their silly games again in an election year, all bets are off. The Senate is a different institution from the House. A group of Senators can hold considerable power. Of course, the constitutional option's off the table, but so is the filibuster.
(Denny Crane: "Sometimes you can only look for answers from God and failing that... and Fox News".)