From the Texas Constitution:
Article 4
Section 8 - CONVENING LEGISLATURE ON EXTRAORDINARY OCCASIONS
(a) The Governor may, on extraordinary occasions, convene the Legislature at the seat of Government, or at a different place, in case that should be in possession of the public enemy or in case of the prevalence of disease threat. His proclamation therefor shall state specifically the purpose for which the Legislature is convened.
http://www.capitol.state.tx.us/cgi-bin/cqcgi?CQ_SESSION_KEY=WNBLQHEEWIIT&CQ_QUERY_HANDLE=136003&CQ_CUR_DOCUMENT=2&CQ_TLO_DOC_TEXT=YESPerry is clearly abusing the power to call special sessions of the legislature. He has stated that he will continue to do so until he gets his way, even though mid-decade congressional redistricting--in the absense of a court order or a public groundswell-- is hardly an extraordinary matter that requires a special session. The fact that the constitution even mentions a "public enemy" or "disease threat" in the context of the power to call special sessions indicates that the framers of the Texas constitution intended special sessions to be called under emergency circumstances only.
Texas Democrats should serve notice to Perry that if he calls a third special sessions designated for redistricting he will have committed an impeachable offense and a gross abuse of gubernatorial power.