By Alana Wise and Jeff Mason
PHILADELPHIA (Reuters) - Hillary Clinton makes her case for the White House on Thursday night, armed with a ringing endorsement from President Barack Obama and the crucial backing of the opponent she beat to become the Democratic Party candidate for November's election.
Capping a Democratic Party convention that has sought to heal divisions from a protracted primary battle, former Secretary of State Clinton, 68, will accept the nomination to run against Republican Donald Trump.
In doing so, she will become the first woman presidential candidate of a major U.S. party.
In her speech in Philadelphia, Clinton needs to make a convincing argument that she can bring about change, while still representing the legacy of Obama, who is nearing the end of his second four-year term with high approval ratings. She also needs to make inroads with voters who find her untrustworthy or unlikeable.
Seeking to rally the party on Wednesday night, Obama offered rousing support for Clinton and an optimistic view of the United States that he contrasted with Trump's vision of a country in crisis.
Clinton, wife of former President Bill Clinton and a former U.S. senator, was likely to issue a similarly upbeat message. She aimed to draw on an idea that has driven her throughout her career, that every American should be given the chance to fulfill their potential, a campaign aide said.
Known as a more effective politician in small gatherings than as a big-event speaker, Clinton has a hard act to follow after well-received speeches this week by Obama and his wife, Michelle Obama, and others such as Vice President Joe Biden.
Clinton, who will be introduced on the stage by her daughter, Chelsea, was still working on her speech on Thursday, the aide said.
On Wednesday night, Obama stressed her experience and skills. "There has never been a man or woman, not me, not Bill - nobody more qualified than Hillary Clinton to serve as president of the United States," he said.
"Tonight, I ask you to do for Hillary Clinton what you did for me. I ask you to carry her the same way you carried me," he said. As he finished, Clinton joined him on stage where they hugged, clasped hands and waved to the crowd.
Clinton, who lost the Democratic presidential nomination to Obama in 2008 and was his secretary of state from 2009 to 2013, promises to tackle income inequality, tighten gun control and rein in Wall Street if she wins the Nov. 8 election.
Trump, a 70-year-old New York businessman who has never held political office, is running just ahead of Clinton in a RealClearPolitics average of recent national opinion polls. They both garner similarly high "unpopularity" ratings.
Trump has hammered Clinton as untrustworthy, and Republicans depict her as a Washington insider who would just continue what they characterize as failed policies under Obama's two-term presidency.
ASSAULT ON TRUMP
The Democratic gathering began on a note of discord on Monday, with backers of Bernie Sanders, the U.S. senator from Vermont who lost the nomination to Clinton, reluctant to get behind her and noisily booing her name.
But Sanders himself has urged his supporters to support her, and a string of party leaders have warmly endorsed Clinton. That contrasted with last week's Republican convention in Cleveland, where many party notables showed their concern about Trump's rhetoric and policies by staying away.
Speakers were scathingly critical of Trump on Wednesday.
Taking aim at Trump's campaign promise to "Make America Great Again," Obama said: "America is already great. America is already strong. And I promise you, our strength, our greatness, does not depend on Donald Trump."
Trump, a former reality TV star, has portrayed the country as being under siege from illegal immigrants, crime and terrorism and as losing influence in the world. He has proposed a temporary ban on Muslims entering the country and a wall along the border with Mexico to keep illegal immigrants out.
Biden called Trump an opportunist with no clue about how to make America great. Vice presidential nominee Tim Kaine, a U.S. senator from Virginia, said Trump is a "a one-man wrecking crew" who cannot be trusted in the Oval Office.
Former New York Mayor Michael Bloomberg, a Republican-turned-independent media mogul, joined the Democratic gathering to attack Trump's history of bankruptcies and lawsuits and call his presidential bid a "con."
Trump has tapped a vein of discontent, particularly among blue-collar white voters, and his campaign seized on the optimism conveyed in Philadelphia to say Democrats are disconnected from reality. Recent opinion polls show nearly 70 percent of people surveyed think the country is on the wrong track.
"They described a vision of America that doesn't exist for most Americans," Trump's campaign said.
"Their entire message could be summed up as: things are perfect, let's not change a single thing," it said in a statement on Wednesday night from policy adviser Stephen Miller.
While anti-Clinton protests from die-hard Sanders supporters have calmed since Monday, some Sanders backers said they were still not entirely convinced to vote for Clinton.
Kate Sherman, 31, a dishwasher and Airbnb host serving as an alternate delegate for Oregon, called the convention "such a wide spectrum of emotion." She said on Wednesday night that she needed time to "reflect and process" the events of the week before she could make up her mind about the general election.
(Additional reporting by Amy Tennery, Emily Stephenson, Luciana Lopez, Jonathan Allen, Steve Holland, Doina Chiacu and Amanda Becker; Writing by Frances Kerry; Editing by Jonathan Oatis)