Bernie Sanders' campaign derided media organizations Monday night for declaring Hillary Clinton the presumptive nominee of the Democratic Party, arguing that her purported win is dependent on unpledged "superdelegates" who will not formally vote until the party's convention in July.
"It is unfortunate that the media, in a rush to judgement, are ignoring the Democratic National Committee's clear statement that it is wrong to count the votes of superdelegates before they actually vote at the convention this summer," spokesman Michael Briggs said in a statement.
"Secretary Clinton does not have and will not have the requisite number of pledged delegates to secure the nomination. She will be dependent on superdelegates who do not vote until July 25 and who can change their minds between now and then," he said, adding "Our job from now until the convention is to convince those superdelegates that Bernie is by far the strongest candidate against Donald Trump."NBC News, the Associated Press and other media organizations named Clinton as the presumptive nominee based on both her pledged and unpledged delegate counts.
Sanders has argued that superdelegates — elected officials and other party leaders who are not bound to vote for the candidate their state selected in its primary contest — should not be counted in the final tally even if they have made formal commitments to individual candidates.
His campaign believes that they can still put the nomination within reach for the Vermont senator by convincing Clinton-backing superdelegates to switch their support to Sanders, who they note performs better than Clinton in hypothetical head-to-head contests against GOP presumptive nominee Donald Trump.
Clinton supporters counter that the former secretary of state also leads among pledged delegates, which each candidate accumulated based on their performance in the Democratic primary contests to date.
Clinton currently has 1812 pledged delegates and 572 superdelegates, by NBC News's count, while Sanders has 1520 pledged delegates and 46 superdelegates.
She also leads Sanders in the popular vote.
Another factor complicating Sanders' hopes to convince superdelegates to change sides is his consistent allegation throughout the campaign that the Democratic nomination system is "rigged."
To woo superdelegates, he would have to convince the very party activists he has derided as part of a broken system to change their allegiances, in many cases defying the will of the voters in their home states.
Clinton's campaign tried to downplay the "presumptive nominee" label Monday night, noting that voters in six states head to the polls on Tuesday.
"This is an important milestone, but there are six states that are voting Tuesday, with millions of people heading to the polls, and Hillary Clinton is working to earn every vote," campaign manager Robby Mook said in a statement.
"We look forward to Tuesday night, when Hillary Clinton will clinch not only a win in the popular vote, but also the majority of pledged delegates."
This story originally appeared on NBCNews.com.