An attorney for three East Texans suing the state over congressional redistricting was confident Monday the U.S. Supreme Court will hear the case next year.

"I'm 110 percent positive they are going to accept the case for review," said Richard Gladden, who represents three Cherokee County Democrats hoping to nullify congressional districts the Legislature produced in fall after three contentious special sessions.

Gladden filed arguments Monday in response to a state motion Wednesday in which Texas Attorney General Greg Abbott's staff argued that states may redraw lines outside the once-a-decade format because the U.S. Constitution doesn't specifically forbid it.

The state's filing on Wednesday was in response to a June 3 request by the high court for Texas' side of the argument. Gladden said then that the court was indicating an interest in the case by asking Texas to file the optional response the state had declined to write.

Opponents of redistricting filed appeals to the Supreme Court in the spring after a federal court upheld the state's new lines. The lawsuit filed by the East Texans argues chiefly against mid-decade redistricting. The other four lawsuits initially relied on arguments of racial discrimination, but three of those now challenge mid-decade redistricting.

Gladden said he expects the court to announce in early October that it will hear the case early next year.

"I expect a decision by mid-May, and a special election to be ordered by ... early summer," Gladden said.

Abbott's office declined to comment on the case, but sent a copy of last week's motion asking the court to uphold the lower court's decision.

"Each set of appellants has a different theory as to why they believe 'mid-decade' redistricting should be judicially prohibited," the filing reads. "Although creative, none of these theories is persuasive."

The Cherokee County plaintiffs argue that the absence of a constitutional ban on mid-decade redistricting doesn't leave the states free to do so. Presidential and congressional elections are held by statute on the first Tuesday of even-numbered years, but there is no law or constitutional provision forbidding states from electing congress members more often.

"That's basically the argument they are making," Gladden said. "They can't do that."