WASHINGTON — (CNN) Hillary Clinton will shatter another glass ceiling on Tuesday when she becomes the first female presidential nominee of a major party in the nation’s 240-year history.

The former first lady, New York senator and secretary of state, will formally be installed as the head of her party in Philadelphia as she seeks to unite Democrats after a fractious primary against Bernie Sanders and to win a third consecutive White House term for her party.

The roll call vote began shortly after 5:20 p.m. after emotional nominating speeches for both Clinton and Sanders and raucous cheers for both candidates.

Sen. Barbara Mikulski of Maryland emphasized the historic nature of the moment in nominating Clinton.

“On behalf of all the women who’ve broken down barriers for others, and with an eye toward the barriers still ahead, I proudly place Hillary Clinton’s name in nomination to be the next President of the United States of America,” Mikulski said.

As part of the push to bring Democrats together, following repeated shows of dissent from disenchanted Sanders supporters from the floor on Monday, the Vermont senator’s campaign is asking for his home state to go last in the roll call.

He would move for Clinton to be acclaimed the party nominee unanimously, his spokesman Michael Briggs said Tuesday.

Such a move would reprise Clinton’s similar gesture at the 2008 Democratic National Convention in Denver, after her own divisive primary duel against then-Sen. Barack Obama.

Each state in the roll call will be called in alphabetical order to announce their vote tally for Clinton and Sanders — a process that will eventually bring the former secretary of state over the delegate threshold to clinch the nomination over Sanders.

The self-proclaimed democratic socialist won nearly 2,000 delegates during his insurgent campaign, but told his supporters on Monday night in that they had no choice but to unite around Clinton to ensure the defeat of GOP nominee Donald Trump.

The nominating formalities on Tuesday night will mark a moment of vindication for Clinton who emerged from the wreckage of her unsuccessful 2008 bid — in which she started out as highly favored — to serve as secretary of state in Obama’s “Team of Rivals” cabinet.

But she faces a grueling campaign against Trump, who has engineered a polling bounce after his own convention in Cleveland last week and is now locked in a close race with the soon to be Democratic nominee.

Clinton can however draw on political lesson learned after her long career in the glare of the public spotlight.

This year, the Clinton campaign and the candidate herself appeared determined to apply the lessons from her defeat eight years ago to her second White House bid, running a notably different campaign.

Hillary Clinton has one big advantage over Donald Trump heading into November: hindsight.

Clinton has also undertaken a personal journey since her losing effort eight years ago.

Clinton’s daughter, Chelsea, got married and gave birth to two children.

The experience of becoming a grandmother, in particular, seems to have softened Clinton as a candidate, helping her become more comfortable grounding her candidacy on her personal background and family story.

After she crossed the threshold to clinch her party’s nomination in June, Clinton’s victory speech drew inspiration from her late mother.

“I wish she could see her daughter become the Democratic nominee,” Clinton said of Dorothy Rodham, in a striking departure from 2008 when she was reticent to discuss her mother.

The political drama with Sanders and controversy over Democratic National Committee emails that show staffers has done little to dampen the excitement among Clinton allies.

Michigan Democratic Rep. Dan Kildee told CNN on the floor of the convention that this is a moment in American history that “we should not take lightly or take for granted.”

“As a father of a daughter and a grandfather of a granddaughter, knowing that my daughter and my granddaughter will grow up in a country where that barrier has been broken is something that’s not just history for our nation but it’s personal,” Kildee said. “And I’ll remember it that way.”