This week marks a flashpoint in an escalating and unprecedented fight over redistricting, with the country’s two most populous states taking center stage and control of the US House during the second half of President Donald Trump’s term potentially at stake.

Texas Democratic lawmakers who fled the state to deny a quorum are making their way back, each on their own timeline, multiple sources familiar with the matter told CBS News.

Texas Democrats are fretting over a likely primary battle between Reps. Lloyd Doggett (D-Texas) and Greg Casar (D-Texas) as Republicans move toward passing a new congressional map that pits the two incumbents against each other.