Democrats are split on whether Biden would be the party's best nominee in 2024 if he runs for reelection: new poll

• A new NBC/Marist poll has some troubling numbers for President Joe Biden's reelection chances.
• Democrats are split 41% to 41% on whether Biden has the "best chance" to win in 2024.
• His intraparty approval remains high, and Biden has not fully committed to running for reelection.

One question in the latest NBC/Marist poll could spell early trouble for President Joe Biden's efforts toward reelection, should he choose to run again in 2024.

While his intraparty approval is still holding strong at 85% is - despite a continued downward trend in his overall approval rating, fueled largely by the withdrawal from Afghanistan and the public souring on his pandemic response, particularly among independents - his standing as the presumptive nominee is a different story.

Just 41% of Democrats picked Biden when asked if the party would have "a better chance of winning the presidency in 2024" with him as the nominee. Another 41% picked "someone else," leaving the party split.

Normally, an incumbent president is considered a lock to have the backing of their party heading into reelection. With Biden, that norm comes with some caveats.

The first one is his age. At 78, Biden is the oldest serving president in US history.

The other major caveat is what Biden has said about running for reelection, stopping short of a full commitment and instead saying it's his "plan" and "expectation" to run again in 2024.

As Aaron Blake of The Washington Post outlined in a Monday analysis, the wording of the NBC-Marist question is tricky because it does not directly ask whether Democrats want Biden atop the ticket, but if he has the best chance of winning the general election as the nominee.

What makes the 41% number uniquely troubling for Biden

When asked the same question in 2010 about former President Barack Obama, he was backed by 52% of Democrats compared to 37% who wanted someone else.

Similar to other components of the Biden presidency - such as inflation and messy foreign affairs - the closest historical parallel lies in the Carter administration.

Former President Jimmy Carter saw similar lackluster support in a New York Times/CBS poll, with just 23% of Democrats saying they'd back him in a primary challenge for reelection. Carter ultimately prevailed over the late Sen. Ted Kennedy of Massachusetts in the 1984 Democratic primary, but eventually lost to former President Ronald Reagan.

As Insider's Robin Bravender recently reported, allies of Vice President Kamala Harris are fretting over a hypothetical scenario in whichBiden bows out of running in 2024 and she ends up getting a primary challenge from Pete Buttigieg, the transportation secretary and her 2020 primary foe.

With a full year left before the 2022 midterms, polls like the NBC/Marist one are less consequential for decision makers in office and on the campaign side.