WASHINGTON

Voters in the heavily Democratic state of California approved a new congressional map Tuesday evening that is intended to counter an effort led by US President Donald Trump to bolster Republican chances in next year's midterm elections.

Proposition 50 was put forward by Gov. Gavin Newsom in response to an earlier effort in the Republican-led state of Texas to flip five House seats in next year's critical national contest.

Prop 50, known as the "Election Rigging Response Act," seeks to counter Texas' midcycle redistricting by redrawing district lines to give Democrats a chance to win five seats in the western state's congressional delegation.

The Associated Press declared the ballot measure approved at 11 pm Eastern Time, the same time polls closed in California, an indication that the final tally is expected to be lopsidedly in favor. Some 64.5% of voters cast their ballots in favor of Prop 50, the sole statewide question during the off-year election cycle, with 59% of votes counted.

The effort comes as Trump seeks to maintain Republican control of the House during the final two years of his presidency. The party in power, in this case Republicans, typically loses seats in Congress during midterm election cycles.

Redistricting is normally done every 10 years following a census, making Trump's appeal to Republican governors exceedingly exceptional.