On July 25th House Republicans (with six Democrats) passed a resolution condemning her for failing to “secure the border”. Donald Trump talks about her potential presidency in apocalyptic terms. “Kamala Harris will make the invasion exponentially worse,” he told reporters. “Our whole country will be permanently destroyed.”

In 2016 Mr Trump manufactured a border crisis to whip up fear and loathing. But now the crisis is real: migrant encounters at America’s southern border have surged during the Biden administration. There were nearly 2.5m apprehensions at the border in fiscal year 2023, a record. Encounters have fallen by more than half since their peak in December thanks to increased enforcement from Mexico and an executive order that Mr Biden signed in June tightening asylum. But polling from The Economist and YouGov suggests that 14% of registered voters view immigration as the most important issue facing the country, second only to inflation.

In 2021 Mr Biden tasked Ms Harris with looking at the “root causes” of migration in Central America. Republicans have interpreted this broadly, dubbing her the administration’s “border tsar” and placing the blame for high levels of migration at her feet. One of the biggest challenges of her campaign will be countering these claims, and persuading voters that she has a plan to fix the problem.

So far that plan is elusive. Her record offers few hints. As with other issues, Ms Harris has changed her mind on immigration to suit her ambitions. When she was the district attorney of San Francisco, her tough-on-crime policies extended to immigration. She annoyed progressive Democrats by supporting a policy that required law enforcement to refer undocumented juveniles who were arrested to immigration authorities. As California’s attorney-general she worked with federal officials to disrupt drug-trafficking.

But she embraced more progressive, and outlandish, policies as a presidential hopeful. The abject cruelty of Mr Trump’s policy of separating families at the border, and photos of children in cages, led many Democrats to call for abolishing Immigration and Customs Enforcement (ICE), the agency tasked with detaining and deporting migrants. “We’ve got to critically re-examine ICE,” Ms Harris told MSNBC, a left-wing cable news channel. “And we need to probably think about starting from scratch.” During her short-lived campaign she supported government-provided health care for undocumented immigrants and civil penalties, rather than criminal ones, from crossing the border illegally. These statements have already become fodder for Republican attack ads.

As vice-president her record on immigration is scant. Ronald Klain, Mr Biden’s former chief of staff, told the Atlantic that Ms Harris was not thrilled about her assignment to tackle the causes of migration in the Northern Triangle countries of El Salvador, Guatemala and Honduras by encouraging development, democracy and the rule of law. During a trip to Guatemala she had a stark message for would-be migrants: “Do not come.” But when she was asked why she had not been to the southern border, she replied, defensively, “And I haven’t been to Europe.”

She can point to some progress. Ms Harris raised more than $5.2bn from private companies to promote development in the region. Central America’s governments are more stable, and migration from the Northern Triangle has fallen. But the source of that stability differs wildly from country to country. El Salvador’s strongman president, Nayib Bukele, has locked up 1% of the country’s population. In 2023 the election in Guatemala of Bernardo Arévalo, an anti-corruption reformer, was a success for American diplomacy. Sanctions on Guatemalan elites who tried to keep Mr Arévalo from taking office helped ensure the transition of power. But it is unclear how involved Ms Harris was. “She set the initial tenor in what expectations were on good governance…but most of the actual policies were driven by the State Department,” says Andrew Selee, president of the Migration Policy Institute, a think-tank.

Even so, her work in Central America has not seemed like a priority. She has visited the region only twice. Mr Biden, who was tasked with a similar job during the second term of his vice-presidency, visited Latin America 14 times.

In some ways the “root causes” strategy is a hangover from an earlier time. As recently as 2020 migrants from Mexico and the Northern Triangle accounted for the vast majority of encounters at the border. But during the Biden administration, the southern border has become a global crossroads. Migrants from Ecuador, China, India and Turkey try their luck. Promoting development and democracy was never a way to cut migration in the short term. Now it is impossible to have a “root causes” strategy for the entire world.

Ms Harris knows the border is a political liability for her. She will try to remind Americans of Mr Trump’s more draconian policies. She is considering Mark Kelly, a senator for Arizona and a former astronaut, as a potential running-mate. Mr Kelly persistently called for increasing border security years before Mr Biden signed his executive order. 

She may well continue her boss’s strategy of carrots and sticks: ramping up enforcement while finding new legal pathways for undocumented migrants ingrained in their communities. Her biography is proof that such ideas can coexist. “I expect her to sound like a prosecutor when she talks about the border,” says Mr Selee, “and like the child of immigrants when she talks about immigration and America’s future.”

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