JEFFERSON CITY — The Missouri House voted Tuesday to put another roadblock in the path of the push to merge the city of St. Louis and St. Louis County.

Under legislation given preliminary approval by the House on a voice vote, voters in St. Louis and St. Louis County would have to approve the merger proposal backed by the civic group Better Together, which is slated for a statewide vote in 2020.

Rep. Dean Plocher, R-Des Peres, who is sponsoring the proposed resolution, said there are merits to discussing how to improve the region, but the rest of the state shouldn’t be able to force the merger on the people of the city and the county.

“I’m all for making the region better. It’s the process I have a problem with,” Plocher said.

Rep. Bruce DeGroot, R-Chesterfield, said voters in his district are “downright hostile” to the idea of a merger.

The legislation approved Tuesday, House Joint Resolution 54, aims to amend the Missouri Constitution by requiring any merger to be approved by a majority of voters within the county or city set to be merged.