A ProPublica/Texas Tribune review of federal spending data shows more than 200 contract modifications, at times awarded within just weeks or months after the original contracts, have increased the cost of the border wall project by billions of dollars since late 2017. This is particularly true this year, in the run-up to next week’s election. The cost of supplemental agreements and change orders alone — at least $2.9 billion — represents about a quarter of all the money awarded and more than what Congress originally appropriated for wall construction in each of the last three years.