Bernie Sanders must sign an undertaking stating that he will run as a democrat

Sen. Bernie SandersBernard (Bernie) SandersSanders reports that M raises M in less than a day. The memo: The launch of WH by Bernie Sanders sharpens the "socialist" question Gillibrand uses the tweet Trump Jr. to raise funds MORE (I-Vt.) Plans to sign an undertaking stating that he will run as a Democrat in his candidacy for the presidency in 2020 and that he will govern as a democrat when he is elected, told CNN campaign advisor Jeff Weaver.

The revelation came a day after Sanders announced his intention to run for president again in 2020 after an unsuccessful but competitive offer in 2016.

Sanders, an independent from Vermont, has angered some Democrats for not having fully adopted the party in the past, said CNN.

Under the new rules of the Democratic National Committee, Democratic candidates for party candidacy will be invited to make a written pledge to run for office and to govern as a member of the Democratic Party.

A DNC official told CNN that, in the coming days, the DNC would submit to candidates who have already announced their candidacy or formed an exploratory committee a form that they would be invited to return, confirming their intention to present themselves as democrats.

"All the additional candidates who will participate in the race will receive the same information and will have to return the form within the same deadline," added the official.