Is Trumps wall metaphor or factuall~~"But negotiators are somewhat confused by what Trump means when he calls for a wall."?

A physical wall guarding 100% of the border between the USA and Mexico is unnecessary, not wise and unlikely to be built. Securing the border is Essential and a Wall is the Best solution for most of that region. Other security measures will be essential also.

No one "solution" can remedy all the potential problems.

I'd call that a use of the term "Wall" to be metaphor and I'd call those who take it Literally: Uninformed or unwise.

The wall was originally, and still is, just a con job to con the cons out of their votes. He'll keep harping on it so they don't claim he was just talking out his ^ss. Butt he wood only pursue it if he could profit from it personanally.

"Congress is confised" is metaphor for just how lame they are!

He has 5 prototypes for an actual physical wall. Of course, it won't cover the entire border. Only where it is feasible. Electronic technology will likely cover the rest.

He means a literal wall. He has shown a willingness to accept a fence that he still calls a wall. But really, you are asking us to interpret the speech of a man who contradicts himself pretty well daily. We cannot put any faith in his words because he is a liar. Only a fool tries to interpret the truth in the words of an open liar.