In the USA, any immigration force was used for racist purposes. It is not needed at the federal level. Governors and mayors are the best judges of dangerous people in their states.
Customs is still a viable need in the USA so long as customs are a reasonable cost. Border Patrols are the eyes and ears of local and state law enforcement. The federal border patrols need to be responsible for the borders of the USA, not 200 miles into the interior.
Never in any reasonable person’s political preferences did they believe such horrors as Trump would manifest. He us an abhorrent human being without a moral soul.