If Alexandria Ocasio-Cortez's  upset of Rep. Joseph Crowley (D-N.Y.) on Tuesday was a message from the Democratic base to its leaders: message not received.

In their first spoken comments about the No. 4-ranking House Democrat's shocking loss, party leaders suggested it was more an isolated occurrence than a sign of a restless liberal base.

“The fact that in a very progressive district in New York — it went more progressive than, well, Joe Crowley is a progressive — but more to the left than Joe Crowley is about that district,” House Minority Leader Nancy Pelosi said, according to Politico's Jake Sherman. “It is not to be viewed as something that stands for everything else.”

Asked about whether the party is shifting more toward younger, female, progressive leaders, Pelosi retorted: “I am female. I am progressive. What’s your problem?

Rep. James E. Clyburn (S.C.), the No. 3 House Democrat, pointed the finger squarely at Crowley. “I don’t think he paid close enough attention to those constituents at home,” he said. Clyburn added rather dismissively that “stuff happens.”

“I listened to some of the stuff said in the campaign, and maybe it worked,” Clyburn said. Okay...

The sum total of it made clear Democratic leaders weren't about to be bothered by one of their own being unseated in a primary and weren't about to take it as the latest rebuke to their age or leadership.

And that's not unreasonable, for some of the reasons Pelosi mentioned. As I wrote of Tuesday's result, Crowley's loss came about from something of a perfect storm. He faced a young, dynamic challenger who pushed more liberal policies than he did in a district that went for Hillary Clinton by 58 points. Crowley also hails from a district with twice as many Latino residents as white ones. And he is the first Democratic House incumbent this year to lose a primary to a more liberal challenger. This, technically speaking, is one isolated incident — at least so far. And plenty of more pragmatic, moderate nominees have emerged in other Democratic primaries.

But it's also one of a number of signs that the Democratic base is at least somewhat restless. Not all of them have manifested themselves in election results, mind you, but they are there. It's Sen. Bernie Sanders's 2016 campaign. It's the growing number of candidates and incumbents declining to support Pelosi for speaker. It's 2020 hopefuls feeling compelled to shift left on issues such as Medicare-for-all and the minimum wage.

Pelosi, Clyburn and their ilk have plenty of reason to argue this isn't about shaking up leadership, because they are leadership. And Pelosi's chance of regaining the speaker's gavel is already imperiled. Having people believe she is an iceberg beneath Crowley's loss isn't what she needs right now.

But House Democratic leaders' posture here is likely to exacerbate whatever unrest currently exists. If you are an activist looking to shift the course of the party and you see the muted responses to Ocasio-Cortez's win, you've got to think it's double-down time. House Democratic leaders are clearly not going to concede any ground they don't have to, which means it must be taken from them.

We'll see if they've got the numbers to make more “stuff happen.”