Sen. Doug Beck, D-Affton

Sen. Doug Beck, D-Affton, speaks Thursday after the Senate approved a measure making it harder to pass a constitutional amendment proposed by an initiative petition.

Legislation to add a new barrier to amending the Missouri Constitution by initiative petition passed the state Senate Thursday on a party line vote.

With 22 Republicans in favor and nine Democrats opposed, the Senate sent the House a proposal that would require a statewide majority and a majority vote in five of the state’s eight congressional districts to pass a constitutional amendment resulting from an initiative petition or a state convention.