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Hillary Clinton now has the necessary delegates to claim the Democratic presidential nomination. The Associated Press said so Monday, based on weekend primaries in Puerto Rico and the Virgin Islands and on superdelegates who had decided to back her since the last time they were canvassed.

But there is more here than the AP’s tally and Clinton's support among the party establishment. With Tuesday’s primaries in California, New Jersey and four other states, Clinton finally amassed a majority of pledged delegates — the ones awarded based on the actual outcome of elections. What’s more, when all of the votes are counted, her popular vote advantage over Bernie Sanders (3 million votes going into Tuesday) will likely give her a double-digit victory.

And yet, at least as of Tuesday, Sanders was insisting that he will take his fight to the Democratic National Convention in Philadelphia next month.

Why? For all of his complaints about a rigged process, by any meaningful metric he came up short. He trails Clinton in delegates, pledged delegates, raw votes, number of states won and number of swing states won. And his main argument — that he could win if only large numbers of superdelegates switched their support to him — is contrary to his past positions that attacked the very existence of superdelegates.

Rep. Grijalva: Party unity is a two-way street

Could an unusual set of circumstances still prevent Clinton from becoming the first woman to win a major party nomination? Sure. That's why she's the called the presumptive nominee until the Democratic delegates vote in late July. But counting on some highly improbable scenario is hardly reason for Sanders to continue.

Perhaps Sanders will change his mind in the coming days and suspend his campaign. Perhaps he will continue on in a way that doesn’t explicitly criticize Clinton. Or perhaps he will throw a temper tantrum if the party does not embrace his progressive platform.

Anything less than a concession would risk splintering the party. And for someone who has fought most of his life for liberal causes, that would be the ultimate counterproductive behavior.

This year’s election has exposed a rift among Democrats between traditionalists who favor center-left policies and a coalition of young and anti-establishment groups pressing for a more liberal approach.

These differences might seem large to someone who favors an expansive Medicare-for-all approach, or who is miffed by Clinton’s ties to Wall Street. But they pale in comparison with the gulf between Clinton and Republican Donald Trump. Whatever progressive voters might see as Clinton’s shortcomings, she is not running a campaign based on ethnic exclusion and discrimination.

A template for what Sanders ought to do is provided by Clinton herself. In 2008, she fought a highly contentious campaign against then-Sen. Barack Obama. She got a lot closer to winning than Sanders did this year. The 18 million votes she received in the primaries and caucuses represented a slight majority of the popular vote (if you count the tally from a disallowed primary in Michigan).

But she came up short in both pledged delegates and superdelegates. And just days after the final primaries, she conceded with a speech boasting of the 18 million cracks in the glass ceiling that her campaign had caused.

This year, the Democrats could win a third consecutive White House term for the first time since 1940. But they could risk blowing it all with a destructive fight between the near left and the far left.

USA TODAY's editorial opinions are decided by its Editorial Board, separate from the news staff. Most editorials are coupled with an opposing view — a unique USA TODAY feature.

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