By By Julie Pace and Ken Thomas The Associated Press PHILADELPHIA - Ending months of animosity, Bernie Sanders robustly embraced his former rival Hillary Clinton Monday night as a champion for the same economic causes that enlivened his supporters, signaling it was time for them, too, to rally behind the Democratic nominee in the campaign against Republican Donald Trump. "Any objective observer will conclude that - based on her ideas and her leadership - Hillary Clinton must become the next president of the United States," he declared in a headlining address on the opening night of the Democratic convention. President Bill Clinton, watching from the audience, leapt to his feet and applauded, as did most of the delegates filling the convention arena. Sanders joined a high-wattage line-up of speakers, including first lady Michelle Obama who delivered a forceful, impassioned defense of the Democratic nominee.