Democratic presidential candidates, Hillary Clinton and Sen. Bernie Sanders, I-Vt,  stand together before the start of the Univision, Washington Post Democratic presidential debate at Miami-Dade College,  March 9, 2016.
Democratic presidential candidates, Hillary Clinton and Sen. Bernie Sanders, I-Vt, stand together before the start of the Univision, Washington Post Democratic presidential debate at Miami-Dade College, March 9, 2016.

U.S. Democratic presidential candidates Hillary Clinton and Bernie Sanders are debating late Thursday in the New York City borough of Brooklyn, just days before next week's key party nominating contest in New York state.

Pre-election surveys show Clinton, who was U.S. secretary of state from 2009 to 2013, with a lead of 10 percentage points or more in New York over Sanders, a senator from Vermont. But the self-described democratic socialist has won seven of the last eight state contests against her and is hoping for an upset win Tuesday.

Clinton, looking to become the first female U.S. president, holds a large lead over Sanders in the race to win a majority of delegates to July's Democratic National Convention, which will select the party's nominee to run in November's national election. That's when voters will pick the successor to President Barack Obama, who leaves office next January.  

FILE - A man speaks in support of a candidate duri
FILE - A man speaks in support of a candidate during a Democratic caucus in Seattle, March 26, 2016. Bernie Sanders won 74 of Washington state's delegates, while Hillary Clinton won 27.

Clinton has not amassed a majority of convention delegates yet, but would move closer to claiming the nomination with a decisive win in New York, her adopted home and the state where voters twice elected her to the Senate.  A victory for Sanders, who grew up in the state, would give him even further momentum as the contest heads to more state-by-state party elections through early June.

Delegates at stake

With a large cache of 291 Democratic convention delegates at stake in New York, Clinton and Sanders have campaigned extensively in the state for days, trading barbs at each other with increasingly intense rhetoric. Clinton now has 1,786 of the 2,383 delegates needed to secure the nomination, compared with 1,107 for Sanders.

Sanders has focused his campaign against the clout of U.S. corporate chieftains and the yawning U.S. income gap between the wealthy and average wage earners. He drew what his campaign said was a crowd of 27,000 people to a rally Wednesday night in New York City, telling them he could win the state primary if there is a large voter turnout, rather than a smaller one that might favor Clinton.

He criticized Clinton for her ties to Wall Street, her support for trade deals and her vote to support the 2003 U.S. invasion of Iraq, a vote she has long since said was a mistake.

Clinton has accused Sanders of being unable to give details of how he would undermine the power of corporate America and enact broad reforms in Washington, including providing free college tuition for students.

FILE - Former President Bill Clinton greets people
Former President Bill Clinton greets people in the audience after speaking in support of his wife, Democratic presidential candidate Hillary Clinton, at the Community College of Rhode Island in Warwick, R.I., April 14, 2016.

The two quarreled in recent days, with each questioning the other's qualifications to be president, but they later softened their remarks.  Sanders acknowledged that Clinton, the wife of former President Bill Clinton, does indeed have the experience to become the 45th U.S. president, while Clinton said Sanders was clearly preferable to either of the top two Republican presidential candidates, billionaire real estate mogul Donald Trump or Texas Senator Ted Cruz, a conservative firebrand in the halls of Congress in Washington.

Sizable Trump lead

Pre-election polls show Trump, who lives in a luxury high-rise building in New York, far ahead of Cruz and a third candidate, Ohio Governor John Kasich, ahead of Tuesday's New York Republican primary.

Trump leads the Republican convention delegate race by a significant margin over Cruz. It remains uncertain, however, whether Trump, a political novice who has never held elective office, can win a majority of delegates before the party's July convention.

Republican presidential candidate, Ohio Gov. John
FILE - Ohio Gov. John Kasich, right, speaks as Sen. Ted Cruz of Texas listens during the Republican presidential candidates debate sponsored by CNN, Salem Media Group and the Washington Times at the University of Miami in Coral Gables, Fla., March 10, 2016.

Cruz and Kasich are hoping to block a first-ballot Trump victory in the hopes convention delegates will turn to them as the party's nominee on subsequent ballots. Some analysts say many Trump delegates could desert him on the second ballot and support Cruz, possibly enough to hand the senator the nomination.

Republicans have not had a contested national convention since 1976, but most U.S. political analysts are predicting a contentious fight extending beyond the first ballot at this year's convention in the Midwestern city of Cleveland, Ohio.

For their part, Trump aides are still predicting the onetime television reality show host will amass a majority of Republican convention delegates ahead of the quadrennial gathering — 1,265, compared with the bare majority of 1,237 of the 2,472 convention delegates needed to claim the nomination.