murum versus limites

"the erection of a [roman] limites sets in motion a play of social forces which are bound to end disastrously for the the builders. a policy of non-intercourse with the barbarians beyond is quite impracticable. whatever the imperial government may decide, the interests of traders, pioneers, adventurers, and so forth will inevitably draw them beyond the frontier." arnold toynbee. a study in history. the photo of the remains of hadrian's is one of what's left, not what was...the wall was anywhere from nine to twenty feet wide and eleven to twenty feet tall depending on what was available locally to build with...some of it was stone...some turf..all of it was built to the fortifaction specifications of the roman legions and it was found not o be economically viable to maintain and defend it...it was not cost effective...on hadrian's death the new emperor, antonius pius, promptly abandoned it and began construction of a wall shoter than the seventy three mile length of hadrian's in the scottish lowlands about a hundred miles north...this too proved impractical and antonius' successor, marcus aurelius abandoned it and returned to hadrian's wall as the defended border...latin for wall is murum which is what these were physically...they were also the more abstract limites, a demarcation of the the limits of empire ( the term was also applied to the internal boundaries between roman provinces )...from the gulf of mexico tot he pacific the us/mexican border is 1954 miles i have found estimates of it's construction costs ( not manning and patrolling it ) anywhere from $15 billion to $49 billion...one wonders about the economic viability of that for what it is proposed to do which is essentially stop central and south american peoples from demographically reclaiming territories lost by mexico in the 1845-48 mexican american war...you can put economics aside...this is about revanchism pure and simple and the animus it engenders in nativists...a boondoggle at best one wonders whether a modern hadrian's wall would be more efficacious than the original...i would invite you to look at the map of mexico and the u s with attention to the coastlines...immigrants driven to water by a wall suddenly, and possibly exponentially, increase the costs involved in securing an abstraction as ephemeral as a national border...lots of coves and inlets to make land in...and with the defacto cubanization of south florida safe havens for immigrant landings are entirely possible...seems a better idea to me to embrace the inevitable and make peace with demographic change..the benefits may outweigh the costs.