As of 2017 the trade deficit was 71Bn. Remittances to MX topped petroleum as the single biggest part of their economy as of 2015.

Cost of Illegals in the US is around 150bn.

Finish the Wall =-5,000,000,000
Trade deficit =71,000,000,000
___________+66,000,000,000

Secure the border including completing the wall , tax all remittances sent to MX not going to a US citizen, and Increase the ICE field agen workforce 10 fold so they have the resources to do their jobs. Expand the immigration courts as necessary to deal with the backlog and new cases.

The wall pays for itself before even a small fraction of the Illegals currently in the US can be remove.

How is it we lose by securing the border again?

Biggestal99 says:

All illegal immigration 200 foot wall around the whole United States.

How will it stop visa overstayers?

Allan