President Barack Obama has asked voters to reject cynicism and fear, and give their full support for Hillary Clinton to succeed him in the White House.
Speaking at the Democratic National Convention in Philadelphia, he said Mrs Clinton never quits.
She'll go up against Donald Trump in November's election – the first female presidential candidate in American history.
Mr Obama says there's no one more qualified for the job.
Meanwhile, Donald Trump has been described as a national security risk after apparently encouraging Russia to spy on US Government emails.
It's been claimed intelligence agencies are responsible for hacking the Democratic National Committee's computers.
The billionaire businessman said he hopes Russia is able to find thousands of emails missing from Hillary Clinton's server: