Call it a stunt or "Hail Mary" pass.  Call it whatever, but Julián Castro discovered that Border Patrol agents enforce the law, as we see in this NPR report:

On Monday, Castro crossed into Matamoros, Mexico, to meet with a dozen asylum-seekers who have been waiting there under the Trump administration's Migrant Protection Protocols policy, also known as Remain in Mexico. 

The asylum-seekers were hoping they could be allowed to wait in the United States for their immigration court dates instead of in Mexico, where they said they faced violence and harassment because they identify as LGBTQ.

Castro walked with the group and their lawyers across the international bridge and asked Customs and Border Protection to allow them in, claiming an exemption to the MPP because of their status.

Thankfully, the stunt backfired when they were sent back to Mexico.

Yes, this was a stunt for someone who is fading quickly and needs a front-page headline.  It is also an insult to the millions who have come here legally by following the process.

PS: You can listen to my show (Canto Talk) and follow me on Twitter.