File photo. / Reuters

Washington, United States

Economy, immigration, incumbency: As the dust just begins to settle on a brutal US election campaign, experts have highlighted key headwinds that contributed to why Kamala Harris failed to block Donald Trump from reclaiming the White House.

Economic malaise

Democratic strategist James Carville famously explained Bill Clinton's win in 1992 with the phrase "The economy, stupid!"

Thirty years later, the maxim has held, with Vice President Harris failing to win over American voters hit by a spike in inflation during her tenure with Joe Biden in the White House.

The Democrats' big loss follows similar setbacks for incumbent parties around the globe during a wave of inflation in the post-pandemic era.

Though US economic data had steadily improved in recent months, surveys continued to show broad negative sentiment among voters, and Trump relentlessly hammered Harris on the campaign trail over elevated grocery and gas prices.

"People still (view) inflation as a problem, because they are not thinking of the year-over-year rate as economists do, but in terms of price levels," said Bernard Yaros, of Oxford Economics.

"It may upset people that essentials are taking up a much larger share of their household budgets," he told AFP.

Immigration wave

As it was in his 2016 upset, immigration was "clearly a factor" in Trump's 2024 victory, said University of Richmond School of Law professor Carl Tobias.

This time, Trump also promised to launch a massive deportation operation to remove millions of immigrants who came to the United States under the Biden-Harris administration.

Illegal border crossings have plummeted in recent months after Biden issued a tough executive order, but it came after record high numbers in the past year that Trump and other Republicans decried as an "invasion."

Harris, whose portfolio included Central American immigration issues, argued Trump used his influence with elected Republicans to kill a bipartisan border bill for political gain.

Republicans argued the border bill was too little, too late.

Ultimately, voters sided with the Trump camp.

Demographic shifts

Preliminary exit polling showed Harris had won around 40 percent of white voters, over 80 percent of Black voters, and about half of both Hispanics and Asians.

Though Trump did not win a majority of any non-white group, according to the same polls, his support among African Americans rose by single digits and jumped by double digits among Hispanics -- a deeply worrying trend for Democrats.

"We've definitely seen among Mexican American males, evangelicals, not college educated, working class... a steady movement towards Trump," said University of Southern California, Annenberg, professor Roberto Suro.

The trend could also be seen "geographically along the border and in places where that have been impacted very directly by this new migration," he added.

Against all expectations, Trump did better than in 2020 with women -- despite abortion rights being a key campaign issue -- and among youth.

Late entry

Biden, who would have been 82 on Inauguration Day, raised worries among many Democrats last year when he announced his decision to seek reelection.

But no major competitor chose to challenge him for the party nomination, and any mention of his possible mental or physical decline was met with denial by the White House.

But a disastrous debate against Trump in June sparked a crisis as concerns over his mental acuity boiled over, with intense party pressure ultimately leading Biden to step aside.

Harris quickly claimed the mantle, but was left with only three months to reset a trailing campaign.

"Much of this Democratic disaster can be laid at Joe Biden's feet. He never should have tried to run for reelection in his 80s, eventually leaving Harris to manage a short substitute campaign that proved inadequate," said Larry Sabato, a political scientist at the University of Virginia.

Biden baggage

Harris struggled to differentiate herself from Biden and his unpopularity.

The vice president found herself trapped on October 8, when a host on the ABC chat show "The View" asked what she would have done differently than Biden. After a moment's hesitation, she said "there is not a thing that comes to mind."

The exchange turned out to be "disastrous" for the Democratic candidate, as David Axelrod, a former Barack Obama adviser, said Wednesday on CNN.

Trump, who complained a run against Biden would have been easier, didn't miss his chance, playing the clip at his rallies and highlighting it in many television ads.