THE KAMALA HARRIS EFFECT ON THE POLLS HAS BEEN DRAMATIC / THE ECONOMIST

Campaign calculus

The Kamala Harris effect on the polls has been dramatic

The latest surveys point to a tightening race

Joe Biden had been one of the most unpopular presidents to seek re-election since the advent of modern polling. 

In April 2023, when he declared his intention to run for a second term, some 41% of Americans said they approved of him. 

More than a year later, after his disastrous debate performance and calls from high-profile members of his own party for him to step aside, his approval rating sank to an all-time low of 37%.

But throughout the intervening period polls showed that the Democratic Party was weathering the storm despite its standard-bearer taking on water. 

When given a choice between Mr Trump and an unnamed Democratic candidate, rather than Mr Biden, Democrats enjoyed a clear lead. 

Who was this mysterious Democrat who could both excite the party’s base and work to woo moderate and undecided voters? 

It seems that the answer may have been hiding in plain sight: Kamala Harris, who became the presumptive nominee in the days after Mr Biden stepped aside.

Although polling is still sparse, early results suggest that the Democratic base is very enthusiastic about their new candidate. 

YouGov, a pollster, found that before Mr Biden’s withdrawal 62% of Democrats said they were enthusiastic about voting in November. 

After he dropped out, that share rose to 79%. 

Favourability towards Ms Harris is a lot higher than for Mr Biden, especially among those who are young, black or Hispanic (see chart), voters whose support had been faltering this year, according to many polls.

In an average of national polls Ms Harris still lags behind Mr Trump, though by a smaller margin than Mr Biden did (one point versus three points). 

Mr Trump led in the ten national polls conducted the week before Mr Biden stepped down from the nomination. 

In the 27 polls since then, Ms Harris has led in 12 and tied in one. 

Whereas third parties tended to hurt Mr Biden more than Mr Trump, early polling since Ms Harris took the helm indicates that the opposite might now be true. 

In recent polling conducted by YouGov, 3% of voters who supported Mr Biden in 2020 said they would vote for a third party rather than Ms Harris or Mr Trump. 

This compares with 9% in the equivalent poll carried out before Mr Biden’s withdrawal, suggesting that some Biden-sceptic third-party voters might be coming home to the Democrats.

But Ms Harris’s entry into the race has done more than invigorate the core of the Democratic base. 

Her favourability ratings are an improvement on Mr Biden’s among moderates and older voters, too. 

Among those who say they are unsure who they will vote for in November or that they are open to changing their minds, Mr Trump has a net favourability of minus 38, compared with minus 30 for Mr Biden and minus 13 for Ms Harris. 

Ms Harris has improved on the erstwhile presumptive Democratic nominee’s net favourability with independents by 17 points.

Citing poor polling for Mr Biden, the Trump campaign has insisted that states which Mr Biden won by large margins in 2020, such as Minnesota and Virginia, are within the former president’s grasp. 

But recent state polling suggests that Ms Harris has narrowed the contest back to the key swing states. 

The averages of three recent polls in Minnesota and two in New Hampshire show her leading by around six points in both states, barely behind Mr Biden’s margins of victory in 2020 and well ahead of polls conducted before his withdrawal.

Meanwhile, she has closed the gap with Mr Trump in the states which are likely to be pivotal in the electoral college. 

Across six polls, she was tied with Mr Trump in Michigan and trailed him by one point in Pennsylvania, states where Mr Biden was trailing by two points and four points at the time he dropped out, according to FiveThirtyEight, an aggregation website.

None of this suggests that Ms Harris is odds-on to win the presidency. 

Nationwide, the election is very close. 

To defeat Mr Trump, she must overcome a big electoral-college disadvantage. 

Early approval from voters may wither as her opponent hones his attacks. 

Still, Ms Harris has succeeded in upending some of the peculiarities of the rematch between Messrs Trump and Biden, reinvigorating the Democratic base. 

She has moved the contest back to familiar battlegrounds. 

Now, there are fewer than 100 days to win it.