Former Vice President Joe BidenJoe BidenHouse clears bill to provide veterans with cost-of-living adjustment On The Money — Dems dare GOP to vote for shutdown, default To reduce poverty, stop burdening the poor: What Joe Manchin gets wrong about the child tax credit MORE said Sunday he would contest the presidential primary nomination at the Democratic convention if Sen. Bernie SandersBernie SandersPelosi says House members would not vote on spending bill topline higher than Senate's Groups push lawmakers to use defense bill to end support for Saudis in Yemen civil war Congress must address the looming debt crisis MORE (I-Vt.) is leading in delegates without securing a majority.
“The rules have been set,” Biden said on CNN’s “State of the Union.”
“I wonder where that view was when he was challenging Hillary when she went in with a commanding lead,” Biden added. “You don't change the rules in the middle of the game.”
Sanders is the only candidate in the field this year to insist that the candidate with the most pledged delegates should be the party nominee. He held the opposing view in 2016 when facing former Secretary of State Hillary ClintonHillary Diane Rodham ClintonGOP political operatives indicted over illegal campaign contribution from Russian national in 2016 Clinton lawyer's indictment reveals 'bag of tricks' Attorney charged in Durham investigation pleads not guilty MORE.
Biden’s commitment to challenge the nomination comes after he won his first primary in South Carolina on Saturday.
Biden is trailing Sanders in the number of pledged delegates as the candidates head into Super Tuesday, when the largest number of states will hold primaries and caucuses including Texas and California.