You act like it's simply a matter of political will.
You say you can come up with a rudimentary plan to secure the border.
The border is roughly 5,000 miles of border with Canada, 2,000 miles of border with Mexico, and 95,000 miles of shoreline.
https://help.cbp.gov/app/answers/detail/a_id/578/~/border-in-miles
So, go ahead, take 10-15 minutes (maybe 20 if you need to take a 5 minute break inbetween for a snack) to come up with a "rudimentary" plan that will "secure" the US border.
Please, post up how much you think it will cost per year, beginning with the initial construction, up to completion, and then onto maintenance. Oh, and don't forget you need to figure out the cost of interviewing every human walking around within the US to determine if they are illegal, and then busing them...somewhere. Oh, and don't forget the studies on how much it is going to cost business/industry by taking away FreeMarket labor. And the studies to determine the economic impact of all of the new regulations and implements your rudimentary plan will need to secure the US border, all 110,000 miles of it.
Once you've come up with that number, decide how you're going to pay for it. Note well that we're not allowed to add new taxes, because one US political party has signed loyalty oaths to an individual named Norquist that raising taxes is unacceptable, because Benghazi or Freedom or something.
Ok, there's your assignment. Get crackin'!