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(Elliott Spagat | Associated Press file photo) This Oct. 26, 2017 file photo shows prototypes of border walls in San Diego. R... (Gregory Bull | Associated Press file photo) In this Oct. 19, 2017 file photo, crews work on a border wall prototype near th... (Gregory Bull | Associated Press file photo) In this Oct. 19, 2017 file photo, crews work on a border wall prototypes near t... (Gregory Bull | Associated Press file photo) In this Oct. 19, 2017 file photo, people pass border wall prototypes as they sta... (Gregory Bull | Associated Press file photo) In this Oct. 19, 2017 file photo, an unfinished border wall prototype stands ne... (Gregory Bull | Associated Press file photo) In this Oct. 19, 2017 file photo, crews work on a border wall prototype near th...