The fourth Democratic debate left little doubt of Elizabeth Warren's front-runner status as Texas candidates O'Rourke and Castro struggle to keep up.
Democrats took the stage in Houston last night for the third debate as candidates sparred over healthcare and immigration.
With the Iowa caucus less than six months away, Castro is running out of time to close the support gap and compete with the frontrunners.
The candidates laid out their promises on expanding government in public education at a National Education Association event in Houston.
The first debate in a crowded field saw Democrats working hard to separate themselves from the pack and placate the party's growing progressive base.
