Today is Super Tuesday, the single biggest day of the primary season, and the once-crowded field of Democratic hopefuls is reduced to four. Former Vice President Joe Biden, Senator Bernie Sanders, former New York City Mayor Michael Bloomberg, and Senator Elizabeth Warren are still in the race on this high-stakes day. Texas has hundreds of delegates up for grabs, second only to California. The 14 states and one territory participating in Super Tuesday will choose more than one-third of all the Democratic delegates ahead of the party's national convention in Milwaukee this summer.