…Next Wednesday marks the deadline for the hundreds of companies interested in building Donald Trump’s signature campaign promise – a “great, great wall” on the US-Mexico border – to submit concept papers detailing their proposals…Matt Kaye of Integrated Security Corporation plans to submit a proposal...Notably absent from the list of interested contractors are any of the large, multinational corporations that would probably have the capacity to carry out the 1,000-mile, $21bn project…Such companies may be put off by toxic politics surrounding the project (62% of Americans oppose building the wall, according to a February poll by the Pew Research Center), and the difficult path to actually funding it…Lawmakers in other states, including New York, Illinois and Arizona, have proposed barring any involved companies from receiving state contracts. The city of Berkeley, California, has already passed a boycott measure…