Trump is right that Obama "built the cages.” But the “kids in cages” trope has become so completely divorced from context and history that it has left the public even more confused about how the American immigration enforcement system works. A quick thread:

I know this history a bit because I was there. In 2014, when Central American families, teenagers and children began crossing the border in the Rio Grande Valley in an unprecedented migration wave, the Border Patrol (and the Obama admin) was completely overwhelmed.

Border Patrol facilities were overflowing, and agents began holding families and children in "sally port" areas -- basically sweltering garages. We obtained a video of these conditions a few days after @brandondarby published photos of overcrowded cells https://www.washingtonpost.com/world/the_americas/central-american-migrants-overwhelm-border-patrol-station-in-texas/2014/06/12/7359534e-2e1b-4a6b-b010-f622f1cac3f0_story.html

The images generated an outcry, and the Obama admin responded by purchasing an empty McAllen warehouse and converting it into a Walmart-sized processing center for families and children. It was clean, spacious, air conditioned. It was a major improvement over the garages.

But it wasn't a humane, dignified place for children and families. Chain-link partitions were added to give the agents visibility and to separate groups: mothers with children in one area, teenage boys in another, etc. Migrants nicknamed it "la perrera" - the dog kennel.

The Obama admin's goal was to quickly and inexpensively set up a safe place to handle migrant children and families in large numbers. But it was Trump's "zero tolerance" family separation system that brought the facility under new scrutiny, because its use changed.

Our immigration system put children in a warehouse with chain-link enclosures before Trump. But under his admin, the government used that infrastructure to systematically take children away from their parents. The inhumanity of the design warped into something even crueler.

All of this underscores the fact that administrations from both parties have struggled to cope with migration pressures using detention and deterrence. But the separation system Trump carried out under "Zero Tolerance" had no precedent, and did not occur under Obama.