The legislation was passed two days after Senate Bill 1750, which also applies to counties above that population threshold and would abolish the nonpartisan county elections administrator position.
Harris County, which President Joe Biden won by 13 points in 2020, is the only county is Texas with a population above 3.5 million, making both bills apply only to its elections.
Hidalgo denounced the legislation as two "election subversion bills" and warned that they will set a "dangerous precedent" for Republican governors who wish to take control of voting in heavily Democratic counties.
"These bills are not about election reform," said Hidalgo at a press conference last week, as the legislation was advancing. "They're not about improving voters' experience. They are entirely about suppressing voters' voices. The reasoning behind these bills is nothing but a cynical charade."
Hidalgo and other officials said at that event that they plan to file a lawsuit against Abbott's administration if the governor signs the bills into law. The Texas Constitution bars state lawmakers from passing laws that apply only to specific jurisdictions, but Republicans' use of a population threshold instead of naming Harris County itself in the legislation may be used at their defense if the lawsuit moves forward.
S.B. 1750 requires Harris County to change how its elections are overseen starting September 1, when Houston will be two months away from voting for its next mayor. Harris County Clerk Teneshia Hudspeth and County Assessor Ann Harris Bennett will oversee elections in the county starting in September.
If, after Hudspeth and Bennett take over, Nelson finds "good cause to believe that a recurring pattern of problems with election administration or voter registration exists in the county," the secretary of state would be permitted to take legal action to remove the two women from office and to install members of her staff in the county's election offices.
Republicans have said Harris County didn't have enough poll workers in the March 2022 primary and that polling locations opened late and ran out of ballots during the November 2022 general election.
"The fact of the matter is, there has not been a single successful lawsuit that proves that there were any kind of problems," said Hidalgo on Sunday. "And I hope that anybody talking about this understands that you are amplifying exaggerations and rumors when you repeat the excuses that these folks are using."
The legislation was passed two-and-a-half months after Abbott's administration announced its takeover of the Houston Independent School District, which has made recent improvements in academic performance that were achieved despite chronic underfunding.
"Houstonians," Emily Eby French, a staff voting rights attorney at the Texas Civil Rights Project, said last week, "will soon live in a different Texas than the rest of us."