A year ago this week, when Senator Bernie Sanders (I-VT) announced that he was running for president, his campaign was widely dismissed as nothing more than a protest candidacy.

Over the past 12 months, Sanders has defied the expectations of many in the political and media establishment. He has proven that there is a vast constituency of voters who are hungry for the progressive ideas at the heart of his campaign. And he has pushed Democratic front-runner Hillary Clinton to take bolder positions. But now, as the delegate math for Sanders grows more daunting, some Clinton supporters and pundits are calling on him to drop out of the race. Sanders should ignore them.

Clinton is almost certain to be the Democratic nominee, but those demanding that Sanders drop out are once again underestimating what he can accomplish by staying in the race. By continuing through the final primaries in June, and entering the July convention with more delegates and primary victories than any true dark-horse candidate in modern history, Sanders still has an opportunity to both influence the direction of the party and increase its chances of victory in the general election.

Read the full text of Katrina’s column here.