Story highlights Bernie Sanders is trying to quell unrest among his supporters

A source said Tuesday he might nominate Clinton to the Democratic Party ticket

(CNN) Bernie Sanders sought to show a united front at the Democratic National Convention Tuesday by asking delegates to accept Hillary Clinton's nomination unanimously and by acclimation.

The plan came at the end of the roll call vote of all 50 states.

"I move that Hillary Clinton be selected as the nominee of the Democratic party for President of the United States," Sanders told the convention.

The move came as Sanders has attempted to tamp down his rowdy supporters, at times getting booed by his own backers as he called for Democratic unity. It follows Sanders' speech to the DNC on Monday, where he empathized with the disappointment of his supporters but said they must support Clinton in the fall.

Vice President Joe Biden, who was doing a walkthrough of the Wells Fargo Arena Tuesday morning, said that Democrats need to "show a little class" to Sanders supporters who are still stinging from his loss.

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