Democrats Seek Unity in Convention Backing ClintonDemocrats opened their national convention Monday in Philadelphia looking to put behind them a contentious primary season with some of their biggest voices uniting behind their presidential candidate Hillary Clinton. Vermont Senator Bernie Sanders, who finished second to Clinton in the Democratic race, said the country needs leadership that brings people together instead of insulting Latinos, Muslims, women, African-Americans and veterans. "While Donald Trump is busy insulting one group after another, Hillary Clinton understands that our diversity is one of our greatest strengths," Sanders said. He spoke about how his campaign was able to push the Democratic Party to adopt several of his proposals, including Wall Street and campaign finance reform and opposing trade agreements like the Trans-Pacific Partnership. Sanders expressed his disappointment in how the nomination process turned out, but said Clinton "must become the next president of the United States." Trump tweets reaction to speech \n\nTrump criticized Sanders on Twitter, saying he "totally sold out" to Clinton and that his campaign was a "waste of time." Sanders quickly fired back. Massachusetts Senator Elizabeth Warren said Trump and his campaign have embraced keeping the powerful on top, as well as racial hatred, bigotry and attacks on women and immigrants. "We've seen this ugliness before, and we're not going to be Donald Trump's hate-filled America. Not now. Not ever," she said. Michelle Obama revs crowd, draws cheers\n\nFirst lady Michelle Obama drew huge cheers from the crowd as she spoke about the importance of those in the White House serving as role models to the nation's children, saying that "our words and actions matter" and that she believes Clinton is the only person qualified to be the next president. "I want a president with a record of public service, someone whose life work shows our children that we don't chase fame and fortune for ourselves, we fight to give everyone a chance to succeed," Obama said. "I want a president who will teach our children that everyone in this country matters." She made several apparent references Trump without mentioning his name, including saying a president cannot have a tendency to lash out and needs to be steady and well-informed. "Don't let anyone ever tell you that this country is not great, that somehow we need to make it great again. Because this right now is the greatest country on Earth," she said, rebutting Trump's campaign slogan "Make America Great Again." Trump slams Cory Booker, mum on Obama\n\nTrump In addition to tweeting about Sanders and Warren, Trump posted a message about a speech by New Jersey Senator Cory Booker. But absent were any words about Obama's speech, a week after Trump's wife Melania spoke at the Republican National Convention with a passage very similar to one Obama delivered in 2008. Booker, who was mentioned as a possible running mate for Clinton before she chose Senator Tim Kaine, drew huge cheers with an optimistic speech about what he sees as the country's ideals. "We can't devolve into a nation where our highest aspiration is that we just tolerate each other. We are not called to be a nation of tolerance. We are called to be a nation of love," Booker said. He described Trump as divisive and said Clinton was the better choice for president. "Hillary Clinton knows what Donald Trump betrays time and again in this campaign; that we are not a zero sum nation, it is not you or me, it is not one American against another. It is you and I together, interdependent, interconnected with one single interwoven American destiny." New opinion poll \n\nTwo new polls Monday showed Trump edging ahead of Clinton in the days following the Republican convention. U.S. presidential candidates typically get a bump in public support after their nominating conventions and Trump showed a sizable 10-point gain in a CNN/ORC poll. The news organization's survey shows Trump with a 48 to 45 percent lead, compared to its last poll showing Clinton with a 49-42 percent advantage. A CBS News national poll showed Trump with a 44-43 percent lead. Bill Clinton to speak Tuesday\n\nClinton's husband, Bill, a former U.S. president, is addressing the convention on Tuesday. Other speakers include House Minority Leader Nancy Pelosi, party interim chair Donna Brazile and a group of mothers whose children have died from gun violence or in clashes with police.