Democrats have credited the decrease to recent actions by the administration to curb illegal immigration, including an executive order signed by President Joe Biden in June that allows US immigration officials to deport migrants without processing their asylum claims.

A recent poll from CBS, the BBC’s US partner, found that 48% of likely voters believe crossings will go up if Ms Harris wins. A vast majority – 72% – said they believe they will decrease under Trump.

The issue came to the forefront of the DNC on Wednesday, with several speakers defending Ms Harris’ record and slamming the former president for standing in the way of a bipartisan border security deal that collapsed in Congress earlier this year.

“Let’s be clear, the border is broken,” said New York Congressman Tom Suozzi, who has called for tougher border security and asylum laws.

In echoing a line frequently used by Republicans to attack Mr Biden’s immigration policies, Mr Suozzi and other Democrats sought to show the party’s shift toward a tougher immigration message on an issue considered to be one of their biggest political vulnerabilities.

Mr Suozzi added Ms Harris “joyfully accepts the challenge to work across party lines, to secure our border, to treat people like human beings”.