(CNN) The big story on Tuesday night was Alexandria Ocasio-Cortez -- the 28-year-old political neophyte who pulled off the upset of the 2018 election in New York's 14th district. And rightly so! Ocasio-Cortez's victory will reverberate around the Democratic political world for months -- and maybe even years -- to come.

But don't overlook another massive story out of the district: Rep. Joe Crowley's loss at the hands of Ocasio-Cortez effectively eliminates an entire generation of politicians that were seen as the future leaders of the party in Washington.

With the three top Democratic leaders in the House all in their late 70s, the gap between that trio and the 30-somethings still getting their sea legs in Congress is vast and stark. It's the 50-somethings who should fill that gap. But they are all gone.

For those wonder, yes, of course, there are 50-somethings still in the Democratic caucus. But future congressional leaders don't just pop up. Younger members with leadership potential are identified early. They've been raising money for their parties and building their political teams for years. They've been accumulating chits from their colleagues. But due to a series of political missteps, an entire class of potential Democratic leaders has been virtually erased.

Crowley, who served as the Democratic Caucus Chairman, was the last of this lost generation remaining. He was openly angling to vault higher up into the leadership following the 2018 elections -- whether or not Democrats retook the House majority this fall. And at 56, Crowley appeared to be the odds-on favorite to replace Pelosi when and if she decided to leave her top spot. (Pelosi, at 78, insists she plan to stick around in 2019 and beyond.)

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