Texas House Democrats left the state Sunday to prevent a vote on the Republican effort backed by President Donald Trump to rewrite the state’s congressional map.

Under threat of fines and arrest, Democratic members of the Texas House left for Chicago to deny the GOP a quorum needed to redraw congressional districts.

To conduct official business, at least 100 members of the 150-member Texas House must be present. Democrats hold 62 of the seats in the majority-Republican chamber. At least 51 Democratic members are leaving the state, said Josh Rush Nisenson, spokesperson for the House Democratic Caucus.