Colin Allred is plowing ahead in his battle to unseat ... will officially kick off the effort with a rally Sunday in Houston.

Texas Republican Sen. Ted Cruz and Democratic challenger Colin Allred, a member of Congress, at their only scheduled debate this month in Dallas. (Shelby Tauber/Pool/Zuma Press) Texas Rep.

Colin Allred several times with chants of “Beat ... but took the stage at her reproductive-rights rally to stump for his run against Cruz.