Biden and Trump travel separately to the US-Mexico border on Thursday. The issue of migration is one of Trump's favorites and was his focus in the 2016 election.
A recent poll shows that immigration is the biggest concern of Americans. Biden accuses Republicans in Congress of not supporting reforms to the immigration system in a bipartisan proposal that failed on February 7. The latest proposal would bar asylum for those who cross the border illegally according to some sort of daily or weekly quota. It would also reject asylum applications on the basis that they carry infections such as tuberculosis.