Former US Secretary of State John Kerry has told the BBC his fellow Democrats allowed the US-Mexico border to be "under siege" during Biden's presidency.
Kerry told Biden the Democratic party had "missed" on the issue of immigration for years, allowing Republicans like Trump to gain political advantage.
"The first thing any president should say - or anybody in public life - is without a border protected, you don't have a nation," Kerry said. "I wish President Biden had been heard more often saying, I'm going to enforce the law."
Democrats, many of whom advocate more relaxed immigration laws and a pathway to citizenship for undocumented migrants, attempted to portray Trump's positions as harsh and discriminatory.
Kerry says that was a mistake.
"Trump was right," Kerry said. "The problem is we all should have been right."