Opinion - Kamala Harris’s surge may not be built to last

In a truly unprecedented presidential election, one of the most-discussed phenomena has been the immense, and rapid outpouring of support that followed Vice President Kamala Harris's elevation to the top of the ticket following President Biden's withdrawal.

As we wrote in early August, almost immediately after Harris secured the nomination, polls began reflecting a "Harris surge."

However, the caveat we noted was that, while there was genuine enthusiasm for Harris's candidacy, particularly among key Democratic constituencies, it was just as likely that what polls were showing was a honeymoon period, as opposed to a genuine, sustainable surge.

Now that Harris has been the Democratic nominee for two months — and with less than 50 days until Americans cast their vote — it is legitimate to ask whether or not the "Harris surge" will last.

There are two principal reasons for these questions. First, Harris's support in the polls has plateaued over the last two months, with no real shift in the race. This despite an impressive debate performance and more time to introduce herself to voters.

Second, although Harris has undoubtedly driven support and enthusiasm among Democrats, it is a lot less clear that she has made inroads with independents or swing voters. Virtually all of Harris's polling gains are due to Democrats. This leaves the possibility that polls are simply reflecting the support of voters who would, in all likelihood, have voted for a Democrat regardless.

This is not to take anything away from Harris, who stepped into an unprecedented role, made up all of the ground Biden had lost to Trump — even overtaking Trump in some polls — and has generated excitement among the base that was non-existent when Biden was the nominee.

Rather, it is to point out that the race has effectively deadlocked despite a number of things working in Harris's favor — her undeniable debate win, Trump's insistence on running a divisive (instead of issues-based) campaign, and a slew of high-profile endorsements.

Put another way, even though virtually everything has gone right for Harris on the campaign trail, the election remains a toss-up, and Harris has not been able to separate herself from Trump.

Indeed, as the New York Times wrote , while two-thirds (67 percent) of likely voters believed Harris performed well versus just 40 percent saying the same of Trump, the presidential race remained deadlocked, with both candidates at 47 percent in the latest New York Times-Siena poll .

Harris's struggle to expand her polling lead is reflected across all polls aggregated by RealClearPolitics. From immediately before the date through Sept. 20, the RealClearPolitics average has shown Harris' lead growing by less than one percentage point. She now leads 49 percent to 47 percent.

Importantly, Harris's 49 percent also underperforms Biden's from four years ago, when he won 51 percent of the popular vote yet barely scraped by in the Electoral College based on less than 50,000 votes in key states.

Moreover, national polls, which are more likely to show Harris with a lead, are inconsistent with data from the swing states that will ultimately decide this election.

Think specifically of polls like the one from Morning Consult showing Harris leading Trump by 6 points (51 percent to 45 percent). Such outlier polls (as that one appears to be) make for highly clickable news headlines and contribute to the narrative of a "Harris surge," even if data from the swing states show something drastically different.

While Harris leads in the must-win "blue wall" states — Michigan (+2), Pennsylvania (+1), and Wisconsin (+1) — Trump has similar leads in Georgia and Arizona (+2 each), with North Carolina a tie, per the RealClearPolitics averages.

Notably, neither candidate's lead in any state is outside of the margin of error.

Taken together, the polls suggest that although Harris has clearly helped Democrats eliminate the enthusiasm gap — there has been a 26 percent increase in enthusiasm among Democrats per ABC-Ipsos polling — this has not translated across the wider electorate.

Further, there are other reasons to question whether the momentum Harris has actually gained will last.

As Alexander Bolton wrote in this publication, "Behind the public jubilation over Vice President Harris's swift rise...Democratic lawmakers are privately anxious about her prospect of defeating former President Trump."

In that same vein, Amie Parnes quoted a Democratic strategist who pointed out that while Harris was successful in "uniting the base" while questioning whether the vice president "can appeal to the voters Democrats have always needed to put us over the top."

It is true that in what is figured to be a close election, every vote counts, and if Harris can drive high turnout, she has a better chance to win.

However, as a polling analysis in the Washington Post suggests , Harris is mainly benefitting from increased support among traditionally Democratic voters, not attracting new swing voters. This is not inherently bad, although it does indicate that far from a genuine "Harris surge," the polls are simply reflecting Democrats coming back into the fold.

Ultimately, the drastic increase in "joy" and "positive vibes" among Democrats ever since Harris' nomination has been impressive. It could very well push her over the finish line, particularly in such a close election.

And yet, based on the data, it appears that declarations that Harris has a truly strong position vis-à-vis Trump are premature. Whether or not Harris can win by bringing in swing voters and moderates, or if she has only reinvigorated her base, remains to be seen.

Douglas E. Schoen and Carly Cooperman are pollsters and partners with the public opinion company Schoen Cooperman Research based in New York. They are co-authors of the book, "America: Unite or Die."