SE Cupp is a CNN political commentator and the host of "SE Cupp Unfiltered." The views expressed in this commentary are solely hers. View more opinion articles on CNN.

(CNN) Joe Biden, while still enjoying his frontrunner status, is facing some challenges during this nascent Democratic primary.

They are unsurprising and often self-imposed.

There's his plagiarism past, brought up again when it was discovered he (or his campaign) had lifted several passages from think tanks and other organizations for his new climate change plan. There's his previous support for the now-controversial 1994 crime bill, which he's still defending, despite progressives' panning of the legislation, particularly because it contributed to the disproportionate incarceration of people of color.

And there's his campaign aides' awkward attempt to explain a 1987 gaffe resurrected by the New York Times -- his claim that he marched during the Civil Rights movement when he most certainly did not.

And now there is abortion.

He just announced--in a speech in Atlanta Thursday--that he no longer backs the Hyde Amendment, the 1976 measure that prohibits federal funding for abortion except in the case of rape, incest and endangering the life of the mother. This is his third position just this week.

Only a day earlier, when asked in a rope line if he'd repeal the Hyde Amendment, he said he would. But then his campaign quickly backtracked, saying he misheard the question and that he still supports the measure.

This naturally unleashed a flurry of responses from his Democratic challengers:

Cory Booker clapped back on NBC : "I think the Hyde Amendment is wrong."

Beto O'Rourke tweeted: "No matter your income or where you live, every woman should have access to health care including abortion."

Kamala Harris weighed in . "No woman's access to reproductive health care should be based on how much money she has. We must repeal the Hyde Amendment," she tweeted.

Others have been, er, less measured. As one abortion columnist hyperventilated in the Washington Post: "Biden's position on this issue should disqualify him from contention for the nomination."

JUST WATCHED Dem presidential candidates attack Biden en masse for support of Hyde amendment Replay More Videos ... MUST WATCH Dem presidential candidates attack Biden en masse for support of Hyde amendment 02:17

It seems Biden has now caved to all that progressive pressure.

Which raises the question: What, exactly, is the point of his candidacy?

The fact is, Biden was right to back the Hyde Amendment on both the principle and the politics.

For starters, as many progressives are surprised to just now discover, Biden has long been a moderate on abortion, even bordering on conservative at times. That includes his past objections to Medicaid funding of abortions.

As NBC recently reported, his personal opposition to abortion might be news to many, but it isn't a secret. Biden is a Roman Catholic who has openly discussed his evolving views over decades.

Among the "surprises" uncovered:

In a 1994 letter to voters he bragged that he'd "on no fewer than 50 occasions" voted against federal funding of abortions.

He even once voted for an amendment to allow states to overturn Roe, a measure that didn't pass and that he considered "the single most difficult vote I've cast as a Senator."

But he's also moderated over time, saying he now supports Roe v. Wade as the law of the land and would not impose his religious views on women. While running with Barack Obama in 2008, he earned endorsements from NARAL and Planned Parenthood.

JUST WATCHED CNN's John King calls out Biden for 'amateur mistake' Replay More Videos ... MUST WATCH CNN's John King calls out Biden for 'amateur mistake' 03:28

In short, his support of the Hyde Amendment was consistent with his long voting record and personal beliefs. That he hadn't abandoned his position made him principled -- something we voters could use more of.

It was also politically prudent.

According to a 2016 poll for Politico by the Harvard T. H. Chan School of Public Health, only 36% of likely voters want to overturn Hyde.

Unless attitudes have significantly shifted since then -- and new polling is needed -- Biden's position was right in line with a majority of Americans.

The truth is, most Americans are not extremists on abortion, despite the extreme new laws in states like Georgia and Alabama.

According to Gallup , only 29% of Americans think abortion should be legal in all circumstances, and only 18% believe it should be illegal in all circumstances.

The Democrats' sudden revulsion over the Hyde Amendment is just that: sudden. The amendment survived three Democratic Presidents -- Jimmy Carter, Bill Clinton and Barack Obama. All at one point enjoyed majorities in Congress. None made any serious attempt to repeal it.

JUST WATCHED How Donald Trump is doing Joe Biden a great favor Replay More Videos ... MUST WATCH How Donald Trump is doing Joe Biden a great favor 02:15

Biden's reasonable approach to the issue was smart. Whereas the rest of the Democratic candidates will find themselves way outside the norm for the general election, Biden was positioned to reach moderates and independents as well as most Democrats.

In his 2007 book, "Promises to Keep," Biden described his position on abortion as "middle of the road."

Wasn't that the point of his candidacy? To occupy a moderate lane that far-left progressives had abandoned over the past few years? To capture the forgotten Democrats in the middle of the country, the voters the party had left behind for the coastal elites?

With his abandonment of the moderate view on abortion, he's ceding not only fertile voting territory but the thing that set him apart from a field of far-left progressives who don't represent a majority of Americans. What's the point in that?

This op-ed was updated from an earlier version on the news of Joe Biden's reversal of his position on the Hyde Amendment.