The Texas Senate's two-thirds rule is generating discussion among candidates for Lt. Governor and those vying for SD 10. The question being discussed, should the Senate do away with the two-thirds rule when the 84th Legislative Session convenes in 2015? For “almost half a century”, according to the Legislative Reference Library, this tradition has been in place. Routinely in the Texas Senate, a blocker bill (a bill not intended to be worthy of serious consideration or passage) is placed on the daily calendar so that two-thirds of the members must agree to suspend the rule so that other bills can be taken out of order and considered. Although set aside occasionally, the rule has traditionally been used to ensure a bill has substantial support before coming to the floor for debate.

More discussion on the two-thirds rule:
Tribune Texplainer – What is the Blocker Bill?
TribLive Conversation – Lt. Gov. David Dewhurst on Two-Thirds Rule
TribLive Conversation – Sen. Dan Patrick