Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Biden, Sanders, Warren Finally Square Off in Democratic Presidential Debate Ken Bredemeier VOA's Russian Service contributed to this report. WASHINGTON -- The 10 leading U.S. Democratic presidential candidates are debating Thursday night, but the focus is likely to be on the three top-polling contenders -- former Vice President Joe Biden and Senators Elizabeth Warren and Bernie Sanders. The other seven will have to scramble to try to edge their way into the top tier of challengers. The nationally televised debate in Houston, Texas, is the third in a string of Democratic presidential debates ahead of next year's party election contests to pick a nominee to face President Donald Trump, the Republican incumbent trying to win a second White House term in the November 2020 national election. The three-hour debate is the first since late July. It also is only a single encounter this time on one night rather than two consecutive nights. Ten more trailing candidates failed to meet Democratic Party requirements to merit a spot on Thursday's debate stage -- campaign donations from at least 130,000 people and at least 2% support in four polls across the U.S. or in states with the earliest voting next year. .