if MAGAs really want to do this, i think they can achieve it pretty easily:
Step 0: As we all know, tazing-your-own-crank level ineptitude is foundational to MAGA
Step 1: identify where they want the border to be
Step 2: start building a wall along that border
Step 3: when/if confronted why they are building a wall, just take a copy of the border wall plans they have for texas and hold them upside down and be like "aw dag nabbit did we do this wrong?"
Step 4: Steps 1-3 are really kind of irrelevant b/c in order to do this they would have to raise money and inevitably some MAGA grifter will take up the task of fundraising to building the confederate border wall and then just pocket all the money while laughing their asses off from some tropical island
Step 5: anyone wanna go in w/ me on starting a non-profit fundraiser to build the confederate wall? Might need something a little more catchy. The State's Rights Wall? the Stem the Tide of Northern Aggression Wall? the SToNA Wall?