Negotiations between the Democrats and Republicans may clarify the materials with which wall, its size, and the location a wall on the border, and other characteristics. Democrats signaled their willingness to erect some kinds of barriers or fences if they do not represent a symbol of racial exclusion. What type of wall Trump will accept, on the other hand, will depend on what right-wing pundits, like Ann Coulter and Rush Limbaugh, are willing to take?
While it seems unlikely that Trump would order another government shutdown, he may decide to declare and national emergency. Such a declaration, if permitted by the courts, would authorize Trump to re-program some funds from military projects and order the Corps of Engineers to begin construction. Even this modest beginning of a wall might provide Trump with enough cover to satisfy most right-wing pundits eradicate it as an issue.