Republicans have blamed his policies for the increase, though experts note external political and economic factors play a substantial role in driving migration.

What experts? Biden and the democrats are the ones literally and figuratively holding the border open for illegal immigrants. When Texas tried to stop it, Biden went over their heads to force them to re-open the floodgates. There is no external or economic factor at play here. Biden wants to flood the country with illegal immigrants, and he wants to get them to be able to vote for him - hence the pushback against voter id, and the attempts to let illegals vote.