Washington CNN  — 

If you asked any smart Democrats on June 28 who they believed, in their hearts of hearts, would be the 2020 Democratic presidential nominee, 9 in 10 would have said Kamala Harris.

The senator from California was coming off a star turn in the first debate of the Democratic primary campaign – telling her personal story powerfully even while effectively exposing Joe Biden’s weakness over his record on busing. She was in command, comfortable on the stage, presidential. 

Now, just 83 days later, Harris is fighting for her political life – pushing all of her political chips into Iowa on the chance that a stronger-than-expected showing in the first caucus is the one thing that can remedy what ails her. “Kamala Harris plots Iowa blitz as campaign stalls,” reads CNN’s headline on Harris’ all-in-on-Iowa move – not exactly the headline you want to begin said blitz.

So what happened? How did Harris go from the clear alternative to front-running Biden in late June to needing to make a drastic strategy change to stay relevant in mid-September?  

The answer is this: No one thing happened. A confluence of things happened.

1) Harris was unable to follow up her strong first debate with similar performances in the second and third debates. Particularly in the second debate, in July, she struggled as her rivals went after her record on health care, among other issues.

2) She couldn’t decide what she wanted to be. Was she the attack dog making the case against the establishment? Was she the tough prosecutor? Was she the unity candidate? The liberal lion? She played all of those roles at some point over the summer. But she has yet to settle on one in particular.

3) Elizabeth Warren happened. Warren’s rise over the past three months tracks pretty closely with Harris’ fall. When Harris announced for president, she was the one with the big crowds and all the excitement. That candidate is Warren now.

4) The health care answer is still not there. On the most important issue to Democratic voters, Harris has been all over the map. She said she was for “Medicare for All.” Then she backed away. Then she said she hadn’t backed away. Then she officially backed away with her own plan that doesn’t call for eliminating the private health insurance industry. Confusion about where Harris stands on such a central issue has fueled broader questions about what, exactly, she does believe in and what she is running on.

None of these factors are insurmountable. There are 137 days left before the Iowa caucuses on February 3 – and, as Harris’ rise and fall have shown, a lot can happen in a lot less time. But her fall is striking because it was so hard to imagine less than three months ago. Maybe her comeback will seem just as unlikely if and when she can make it.

The Point: The arc of Harris’ campaign to date is a lesson to anyone running for office. That lesson? Don’t peak too early.