The lawsuit was brought by conservative Texas activists who have railed against expanded voting access in Harris County, where a record 1.4 million early votes have already been cast. The county is the nation’s third largest and a crucial battleground in Texas, where President Donald Trump and Republicans are bracing for the closest election in decades on Tuesday.

U.S. District Judge Andrew Hanen’s decision to hear arguments on the brink of Election Day drew concern from voting rights activists, and came after the Texas Supreme Court rejected a nearly identical challenge over the weekend.

The ruling came in response to a lawsuit by conservative GOP activists who have filed a battery of court challenges over moves to expand voting options during the COVID-19 pandemic. The challenges have not involved Trump’s campaign.

Another 20,000 or more voters were expected to use drive-thru polling locations Tuesday, said Harris County Clerk Chris Hollins, the county’s top elections official. Several voters who already used the drive-thru centers rushed to join mounting opposition to the lawsuit, including a Houston attorney whose wife was 35 weeks pregnant when she cast her ballot. She gave birth to twins Friday.