It's well-known that death penalty cases take forever to progress through the system. It's less well-known that immigration cases sometimes take (relatively) forever as well.
There's no doubt that the petitioner here, Angel Posos-Sanchez, is removable from the United States. He's been removed before, after all. The central issue is simply whether he's eligible for voluntary departure from the U.S. -- or whether immigration officials get to select the date he gets booted.
All of the decisions below uniformly concluded that Posos-Sanchez gets removed, and that he was stopped and released at the San Clemente checkpoint in September 1990 -- over thirty years ago -- doesn't mean he was "admitted" to the United States. Posos-Sanchez is a citizen of Mexico, but has resided in the United States since 1980.
As today's opinion explains, "in either 2010 or 2011, Immigration and Customs Enforcement removed Posos to Mexico (the record does not explain how or why this removal came about)." Then "Posos tried to reenter the United States at the San Ysidro Port of Entry on March 9, 2011. There, immigration officials stopped the vehicle bringing him into the country and found him hiding in the trunk of the car. Posos admitted to these officials that he lacked the necessary documentation to enter or remain in the United States. They therefore detained him and referred him to the Immigration Court for removal proceedings." Posos-Sanchez was subsequently released on bond in May of 2011.
So his case has been going on now for over a decade. And it's not like he's been bouncing around the various courts or anything; it's a straight shot. He lost before the IJ, he lost before the BIA, he lost in the district court, and now it's 2021, and we're just now getting a Ninth Circuit opinion. Which in turn remands the case back to the immigration judge "to make further findings and conclusions about his eligibility for voluntary departure." So presumably another IJ-BIA-district court-Ninth Circuit round.
Maybe this time, in under a decade or so.