US election explained: How crucial is the issue of immigration?

Since arriving on the US political scene almost a decade ago, Donald Trump has put a major focus on illegal immigration, with his pledge to build a border wall one of the mainstays of his successful 2016 campaign for the White House.
Since losing the 2020 election, he has repeatedly criticised the Biden administration’s record on the border. He claims the Democrats, and Kamala Harris, who he calls the “border czar”, have allowed “millions and millions of people” to illegally enter the US every month.
Polling by the Pew Research Centre shows more than six in 10 voters say immigration will be very important to their vote – up 9 percentage points since the 2020 campaign.
Harris has had to talk tougher on the issue than Joe Biden in 2020, with her campaign website noting the need to “secure our borders and fix our broken immigration system”.
The southern border with Mexico, which stretches for more than 3,100km between California and Texas, is the main crossing point for would-be immigrants. US Customs and Border Protection data counts people who attempted to cross illegally and those who tried to enter legally but are deemed inadmissible. Those who cross undetected are not counted, with the total number of undocumented immigrants in the US put at about 11 million in 2022.
The data show there were about 2.4 million “encounters” with migrants both last year and in 2022 at this frontier, and more than eight million in all during Biden’s presidency. During Trump’s presidency, from 2017 to 2020, there were about 2.4 million such encounters.
The number of migrants crossing illegally at the southern border has fallen in recent months as measures implemented this year by the Biden administration have started to have an impact.
The rise has, in the main, been attributed to people from some South and Central American countries seeking to escape difficulties including poverty, political repression, climate disaster and gang crime. It also comes at a time when migration from poorer to wealthier countries is rising across the globe, according to the OECD and other bodies.
Border crossing attempts plummeted during the Covid pandemic and the high numbers in 2022 and last year are regarded by some as pent-up demand working its way through.
In addition, Biden promised to reverse some of Trump’s harsher measures aimed at stifling immigration, including stopping work on the border wall. Some argue this gave the impression that the US was more open to immigration than it had been.
As the numbers ticked upwards, Biden attempted to introduce major immigration reform, which would have seen hundreds of millions spent on border wall construction, asylum decisions fast-tracked and a greater capacity to deport migrants. It won support from Democrats and Republicans in Congress but stalled due to what the president described as intimidation from Trump, who he claimed saw the measures as being “bad for him politically”. The Trump campaign denied this.
Harris says she will bring back the reforms Biden proposed “after Donald Trump killed the border deal for his political gain” and sign them into law. She also says “our immigration system is broken and needs comprehensive reform that includes strong border security and an earned pathway to citizenship”.
Trump’s website says he will “seal the border and stop the migrant invasion”. The Republican Party says it will restore every border policy of the last Trump administration, halt all releases of illegal aliens into the US, shift some federal law enforcement staff to immigration duties as well as troops stationed abroad, and use advanced technology to monitor and secure the border.