TEMPO.CO, Philadelphia - Hillary Clinton secured the Democratic Party's U.S. presidential nomination on Tuesday, coming back from a stinging 2008 defeat in her first White House run and surviving a bitter primary fight to become the first woman to head the ticket of a major party in U.S. history.

In a symbolic show of party unity, Clinton's former rival, U.S. Senator Bernie Sanders of Vermont, told the chairwoman from the convention floor that Clinton should be selected as the party's nominee at the dramatic climax of a state-by-state roll call at the Democratic convention in Philadelphia.

"I move that Hillary Clinton be selected as the nominee of the Democratic Party for president of the United States," Sanders told thousands of delegates in the Wells Fargo Center, which erupted in cheers.

Capping nearly a quarter century in public life as first lady, U.S. senator and secretary of state, Clinton will become the party's standard-bearer against Republican nominee Donald Trump in the Nov. 8 election when she accepts the nomination on Thursday.

In nominating Clinton, delegate after delegate made the point that the selection of a woman was a milestone in America's 240-year-old history. U.S. women got the right to vote in 1920 after ratification of the 19th Amendment to the Constitution.

Clinton, who promises to tackle income inequality and rein in Wall Street if she becomes president, is eager to portray Trump, a businessman and former reality TV show host, as too unstable to sit in the Oval Office.

But Trump, who has never held elective office, got a boost in opinion polls from his nomination at the Republican convention last week. He had a 2-point lead over Clinton in a Reuters/Ipsos opinion poll released on Tuesday, the first time he has been ahead since early May.

Sanders has endorsed Clinton, but some of his supporters protested in Philadelphia against the party leadership's apparent backing of her during the Democratic primary fight.

Sections of the convention hall were left conspicuously unpopulated on Tuesday night as delegates from strongly pro-Sanders delegations, including California, walked out after Sanders moved that Clinton be named the nominee.

MAKING HISTORY

Earlier on Tuesday, delegates from South Dakota had given Clinton 15 votes, formally ensuring that she had more than the 2,383 votes needed to win the nomination. She emerged with a total of 2,842 votes to Sanders' 1,865.

Delegates chanted: "Hillary, Hillary" as U.S. Senator Barbara Mikulski of Maryland formally put forward Clinton's name for the roll-call vote.

"Yes, we do break barriers, I broke a barrier when I became the first Democratic woman elected to the Senate in her own right," Mikulski said. "So it is with a full heart that I'm here today to nominate Hillary Clinton to be the first woman president," Mikulski said.

Clinton was the early favourite in the 2008 Democratic race but lost a hard-fought nomination battle to first-term U.S. Senator Barack Obama, who went on to become America's first black president.

Supporters of Clinton say her Washington credentials show she has the experience needed for the White House during tough times as the United States tries to hasten its economic recovery and tackle challenges abroad like Islamic State and the rise of China.

Detractors view her as too cozy with the establishment and say she carries political baggage dating back to the start of her husband President Bill Clinton's first White House term in the 1990s.

Polls show many Americans distrust Hillary Clinton, who critics accuse of bending the rules and lacking transparency in her political dealings. Controversy over her use of a private email server for official business while she served as America's top diplomat dogged her during the primary election season.

HELP FROM BILL

Bill Clinton will give the traditional warm spousal endorsement of the nominee in a speech in Philadelphia on Tuesday night.

He will be capping a day in which Democrats want to showcase his wife's achievements on issues such as women and families, healthcare and her time as secretary of state in Obama's first term.

Clinton, 68, will be watching from home in Chappaqua, New York, as her husband speaks, campaign officials said.

President from 1993 to 2001, Bill Clinton is admired by many in the party and left office with high approval ratings. But he carries some liabilities. Liberals, including Sanders supporters, have long been critical of some of his trademark economic policies, such as the North American Free Trade Agreement with Mexico and Canada, and Wall Street deregulation.

He is known as one of the most powerful political orators in the country. At the 2012 Democratic convention, he made an emotional case for the re-election of Obama.

Union leader Richard Trumka said Clinton needed to avoid overshadowing his wife in Tuesday's speech.

"This is not the Bill show, this is the Hillary show and he has to be careful to not even come up to the line of ... I don’t want to say rivalry. If it even looks like that, then he’s done Hillary a disservice and I think he’s cognizant and aware of that," AFL-CIO President Trumka told Reuters.

REUTERS