President Trump has been eager to show progress on construction of his long-promised wall on the border with Mexico. So eager that on Wednesday he sent a tweet showing the building of steel fencing in southern New Mexico with the video sped up to add a sense of both efficiency and urgency.

He retweeted himself on Thursday with the all-caps proclamation “THE WALL IS UNDER CONSTRUCTION RIGHT NOW!”

This is misleading.

The government has built about 700 miles of wall and fencing along the border since 2006. The barriers, damaged by migrants trying to get through them or by the elements, need periodic repairs.

The section of the barrier that Mr. Trump showcased this week was not new construction, but rather replacement for existing fencing. The money for the steel-slatted barrier came from a congressional appropriation in 2017, not from newly authorized spending in the recent deal that averted a government shutdown, or from money the president is seeking to take from other federal projects under his national emergency declaration from last week.