Though the underdogs of the Republican nomination race have all ended their campaigns, Democratic presidential candidate Bernie Sanders pledged to continue his campaign past the primary season and to the Democratic National Convention in July.

The Democratic Party requires a candidate to have 2,383 delegates to win the nomination, and many experts expect Hillary Clinton to win the required number following Tuesday’s primaries, which include California and New Jersey.

Clinton currently has 2,323 delegates while Sanders has 1,547. The bulk of Clinton’s lead, however, comes from her number of superdelegates; she has 544 compared to Sanders’s 46.

The difference between pledged delegates and superdelegates lies in that pledged delegates are acquired through primaries and caucuses while superdelegates are individual party leaders or former party leaders who individually commit to a candidate.

The Republican Party does not have a similar system of superdelegates.

Sanders says he still has enough time to win over enough of Clinton’s superdelegates by the July convention in order to clinch the nomination. 

The moral and political “correctness” of the power of superdelegates has been heatedly contested as of late, and last month Maine Democrats voted to do away with the system of superdelegates entirely, thus stripping Maine superdelegates of their elevated power.

“The media is in error when they lump superdelegates with pledged delegates,” Sanders said, counting himself among those who disagree with the system. “Pledged delegates are real. Hillary Clinton will not have the requisite number of pledged delegates to win the Democratic nomination at the end of the nominating process on June 14. Won’t happen. She will be dependent on superdelegates.”

Superdelegates do not officially cast their votes until July’s convention, and Sanders believes the six weeks between Saturday, when he made his vow, and the convention offers him time to woo the needed superdelegates to his side.

However, it would be unprecedented for the required number of superdelegates to change their pledged vote.

“We understand that we have a steep climb,” Sanders said. “I’m not here to tell you that tomorrow we’re going to flip 300 superdelegates. You don’t hear me say that. But I am saying we are going to make the case.”

While recognizing the difficulty of his task at hand, Sanders exhibits his drive in continuing his fight all the way to the end.

“The Democratic National Convention will be a contested convention,” Sanders said in a news conference in Los Angeles.

Six states hold their primaries on Tuesday, holding the fate of over 800 delegates in their results.