President Obama is hoping to unleash his horde of grassroots supporters on behalf of former Secretary of State Hillary Clinton, and hopes to secure 50,000 volunteers for her campaign in just 24 hours.

On Wednesday night, Clinton's campaign emailed its supporter list, which is augmented by the remnants of Obama's campaign email list maintained by Organizing for Action, along with Obama's appeal.

"In the most difficult moments of the past eight years, you've carried me," Obama wrote.

"You are the best organizers on the planet, and I'm so proud of all the change you've made possible," he said. "As my presidency draws to a close, I'm looking ahead to all the work we have to do in the years to come … Hillary is the only person I trust to continue this mission, and you're the team I trust to make sure she wins the job. I'm looking forward to doing my part to help her win this election. Today, I'm asking you to join me," he wrote.

"The campaign's set a goal of getting 50,000 people to sign up to volunteer — just today! Will you add your name to say you'll be one of them?" he asked.