@hauta
that's a valid question. we have a trade deficit now ONLY because Mexico simply sells more to us, but also due Mexican tariffs: while we are much more lenient on them.
Trump proposes creating a tariff: say, 20% tax. the 58 millions dollar trade deficit, we'd be obtaining 11.6 million dollars worth of.
although John Oliver claims that the wall could cost nearly 70 million dollars, i've looked at it, and the probable cost is 15 million - 25 million, with yearly upkeep fees.
So the tariff would pay for a LOT of the wall... but we wouldn't get the money immediately. However, it is financially possible to do this, and it would help small businesses in the US.
the problem occurs from a lowering of ∑Demand, as well as reactionary tariffs. with that being said, there is NO clear cut answer on Trump's plan, b/c we're relying on Mexico not to raise tariffs themselves, and that's an unknown variable.