Five Republican presidential candidates are in Houston for a final showdown before Super Tuesday: the biggest voting day so far, when 13 states including Texas pick their Republican nominee.
Republican debate: Live updates
Four of the candidates have a shared goal on the CNN debate stage: Stop Donald Trump.
Trump heads into the March 1 contests on a roll after three consecutive state wins. The two men who will flank him on the stage -- Sen. Ted Cruz and Sen. Marco Rubio -- so far have been unable to step out of Trump's shadow.
Gov. John Kasich is starting to come under pressure to quit the race from establishment Republicans who favor Rubio. Ben Carson rounds out the debate, but his poll numbers so far have failed to take off.