(CNN) For the first month of Joe Biden's presidential campaign, it was mostly smooth sailing. That ended, abruptly, over the last 24 hours.

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Consider the hits Biden has taken in just the last day :

* Biden's campaign was forced to clarify that the former vice president still supports the so-called "Hyde Amendment" that keeps federal dollars from being spent on abortion services except in the cases of rape, incest and when the life of the mother is at stake. A video released by the American Civil Liberties Union showed Biden seeming to express support for getting rid of the amendment in a May interview. Biden's reiteration of his support for the Hyde Amendment led to a series of blisteringly critical statements from the abortion rights community. "To support the Hyde Amendment is to block people -- particularly women of color and women with low incomes -- from accessing safe, legal abortion," said Kelley Robinson, executive director of the Planned Parenthood Action Fund.

* In New Hampshire on Tuesday, Biden was asked about criminal justice reform. He said this : "When I wrote the crime bill, which you've been conditioned to say is a bad bill, there's only one provision that had to do with mandatory sentences that I opposed, and that was a thing called the 'three strikes and you're out,' which I thought was a mistake, but had a lot of other good things in the bill." (The crime bill is widely regarded by Democrats as a disaster which led to the mass incarceration of black men.)

Any one of those three storylines are enough to take some shine off of Biden in the race. All three together in the space of 24 hours? That amounts to the first crisis of the campaign for the 2020 frontrunner.

Biden's opponents for the Democratic nomination -- and there are 22 of them -- have been looking for a way in to begin taking shots at the frontrunner for a while now. And to date, they've come up largely empty. Prior to this week, the "best" attack on Biden was that he didn't show up in person at the California Democratic Party annual convention last weekend. Which is, well, pretty weak sauce.

But now Biden -- through a trio of unforced errors by the candidate/campaign -- has opened the door for his rivals to burst through. And they're already trying.

"There is #NoMiddleGround on women's rights," tweeted Vermont Sen. Bernie Sanders on Wednesday. "Abortion is a constitutional right. Under my Medicare for All plan, we will repeal the Hyde Amendment." Added former Texas Rep. Beto O'Rourke : "No matter your income or where you live, every woman should have access to health care including abortion."

The truth is, this sort of reckoning for Biden was inevitable. Even early frontrunners who eventually wind up as their party's presidential nominees always face several moments where it looks like their march to the nomination is going to be slowed or stopped. That's especially true for Biden, who has a very long voting record in the Senate -- decades and decades -- and a proven "ability" to say things that are either impolitic, inappropriate or both.

There is no scenario under which Biden doesn't have to answer for things like his work on the 1994 crime bill or his stewardship of Clarence Thomas' Supreme Court nomination as chairman of the Senate Judiciary Committee in the early 1990s. There's a reason that Barack Obama in 2008 was the first sitting senator to be elected president since John F. Kennedy in 1960. You make votes in the Senate. Lots of them. And over time, the political and cultural climate in the country changes -- and you still have all those votes you have to defend.

To be clear: This is a bump in the road for Biden, not the end of the road by any means. As our CNN national poll released earlier this week shows, the former vice president leads the race by double digits over Sanders, with no other candidate even cresting double digits. He is well-known and well-liked by Democrats. He has already secured a passel of key endorsements and is raising money and building out organizations in the early voting states.

In short: Biden has some ground he can give in this race before he really has to worry.

At the same time, however, slides can be hard to stop. Momentum is a funny thing that, once lost, is tough to get back.

This is the first challenge to Biden's ongoing supremacy in this race. It won't be the last.