The moment Ted Kennedy admitted he wouldn't be the 1980 Democratic nominee

On August 11, 1980 Massachusetts Sen. Ted Kennedy approached a ballroom podium at New York's Waldorf-Astoria to acknowledge what had long been obvious: he would not be the 1980 Democratic presidential nominee.

For almost a full year, Kennedy had waged a tough primary fight against the incumbent Democratic president, Jimmy Carter. But going into the convention, Carter held significantly more delegates - nearly double Kennedy's total.

Instead of surrendering, Kennedy tried to take his fight to the convention floor. His strategy hinged on a suggested change to the party's rules: instead of delegates being forced to vote for the candidate to whom they'd been pledged by election results, Kennedy pushed to allow delegates the opportunity to vote their conscience.

The rule change was shot down by party bosses on the first day of the convention, and Kennedy finally saw the writing on the wall. Around 10 p.m. that night, he stepped into a room full of supporters, waited for the cries of "We want Ted!" to subside, and broke the news.

"I'm deeply gratified by the support I received on the rules fight tonight, but not quite as gratified as President Carter," Kennedy said with a grim chuckle. "President Carter's forces have won an impressive victory this evening. And I am a realist and I know what this result means. I have called President Carter and congratulated him. The efforts on the nomination is over. My name will not be placed in nomination."

Kennedy promised to continue wielding his accumulated clout during the platform fight to come. "I continue to care deeply about where this party stands, and I hope the delegates will stand with me for a truly Democratic platform," he said. "Tomorrow I will speak to the convention about the economic concerns that have been the heart of my campaign and about the commitments and the future of the Democratic Party. I will speak again for the people I have seen and the cause I have carried across this country. Thank you."

And with that, he stepped offstage.

The next evening, Kennedy publicly threw his support behind Carter during a speech before the convention - but it wasn't the full-throated embrace the president hoped to secure from his erstwhile rival. Kennedy's speech did more to burnish his own legacy and the memory of his family than it did to advance Carter's reelection. Afterward, the two men exchanged a perfunctory handshake, but Kennedy avoided the crucial "hands-raised" photo op.

Carter ultimately lost the 1980 election to then-GOP nominee Ronald Reagan - a result many attributed in-part to Kennedy's damaging primary campaign and tepid embrace of the incumbent.

It's been nearly 36 years since Carter and Kennedy faced off, but the memory still looms large for some Democrats who fear the party is headed for a similar problem at the 2016 convention.

As this cycle's primaries and caucuses come to an end, Hillary Clinton holds what many see as an insurmountable delegate lead in the Democratic race. Her rival, Vermont Sen. Bernie Sanders, has turned in an impressive showing, winning approximately 45 percent of the pledged delegates to date. But it simply hasn't been enough: barring some drastically lopsided victories in the few remaining contests, Sanders will finish the primary season with fewer votes and fewer delegates - pledged or otherwise - than his rival.

Will he follow in Kennedy's footsteps and take to the convention a fight he'd almost certainly lose? Or will he emulate the example set by Clinton herself in 2008, when she finished a close second to then-Illinois Sen. Barack Obama in the Democratic primary and endorsed him shortly after the end of primary season, months before the Democratic convention?

Sanders has been cagey on the question of his endgame: At times, he's vowed to stay in the race through the convention in July, but other times he's said he'll stay in until voting concludes in June.

To the casual observer, it may not seem that big a deal: what difference can a month make? But for Democrats anxious to unite the party and take the fight to presumptive Republican nominee Donald Trump, there may be no more consequential outstanding question.