The Democratic National Committee recently adopted a new rule that could keep Sen. Bernie Sanders (I-Vt.) from earning the Democratic 2020 presidential nomination.
The rule, which was adopted on Friday, would prevent political outsiders from seeking the nomination, according to a Newsweek report.
A photo shared on Twitter by Randi Weingarten, a member of the DNC and president of the American Federation of Teachers, showed the committee's rules and bylaws change.
“@DNC #RBC just changed the rules to ensure to run for President as a Democrat you need to be a Democrat,” Weingarten tweeted.
So what are the new rules?
When a Democratic presidential candidate announces his candidacy publicly, he must publicly affirm that he is a Democrat.
Each candidate must also affirm "in writing, to the National Chairperson of the Democratic National Committee" that he is "a member of the Democratic Party; will accept the Democratic Nomination and will run and serve as a member of the Democratic Party."
What does this have to do with Sanders?
Sanders ran a tight race as a Democrat against Hillary Clinton during the 2016 Democratic primaries. He campaigned for universal health care and free college for all Americans, which made him popular among younger voters.
The 76-year-old senator is seeking re-election in 2018 as a Democrat in Vermont. Once he has enough votes to secure the state party's nomination, he will decline the nomination and declare he's running as an independent.
His strategy, which he has used in the past, ensures that he ends up on the ballot while also eliminating other liberal candidates from appearing on the ballot as the Democratic nominee.
Is Sanders planning to run for president in 2020?
The senator has not announced his intentions to make another bid for the presidency, but the Denver Post reported that he's campaigning alongside a 35-year-old black politician and spending time with black lawmakers to talk about "shared priorities."
Sanders struggled to gain support from black voters during the 2016 presidential primary.