“How many miles of wall will complete the task?”
The Comprehensive Plan called for about 1,100 miles of effective barrier, but 221 miles of pre-existing barrier was deemed effective, leaving about 880 miles to be built.
164 of those have been built, leaving roughly 715 miles to go.
569 miles of those are reported as already funded, leaving about 146 to go - but the $3.6 billion in FY 2020 Military Construction money that was announced, has not yet been transferred, and is enough to finish the job.
Although the whole job should be funded and on contract this year, Contractors will be working hard through next year (2021) to deliver the finished product.
So Bottom Line: The whole job is already in the pipeline. Getting the money was the main battle, and enough is now identified.
As we go way down toward the end of the priority list, it gets easier to trade off barrier for more people and technology, so there is probably some trade space (wiggle room) there.
Also, there is a wedge in the ten year baseline budget for building border barrier, inserted under Speaker Ryan, of about $1.5 billion per year, that will run till 2027. That will allow a reasonable annual construction program to continue, constantly extending the total, and quickly patching any new gaps that smugglers start exploiting.
If Biden (or another Rat) is elected, there will be an EO within 48 hours of inauguration stopping construction and starting dismantling. Don't doubt me on that.