The swift decision by the Missouri Supreme Court followed several 11th hour attempts by Republican politicians to keep the proposal off the ballot.

Measures that would protect abortion access are on track to appear on the ballot in 10 states in November, but abortion opponents are engaged in last-ditch legal maneuvering to try to prevent voters from weighing in on the proposals.

Here's what to know about the amendment, what a 'yes' or 'no' vote could mean, and what proponents and opponents think of the measure.