Massive operation but it can be done. The southern wall is built first, then part two – a three sided wall around a Sanctuary Free Zone as pictured:
Wall extends ten miles to sea. Army and navy deployed along the wall, which in fact is three walls, 100 feet apart. Anyone within the wall is safe, anyone venturing out is shot.
Inside the SFZ are the Californian govt, any mayor who declared a sanctuary city and any who voted for it, all the mafia across the US, any leftwing toerags who ever caused any damage, antifa, all the illegals, the criminal politicians – Comeys, Clintons etc.
In they all go. Once in there, they can live as they wish but try to get out and they’re shot. Outside the zone is declared a Sanctuary Nation.