U.S. District Judge Gonzalo Curiel is set to hear arguments Friday from the state of California and environmental groups opposed to a part of President Trump's border wall because it would endanger a species of butterfly and a Mexican shrub.

In case you're curious, it is the Quino checkerspot butterfly and the Mexican flannel bush.

The Trump administration cannot sidestep the National Environmental Policy Act and the Endangered Species Act, groups like the Sierra Club are arguing.

Yet, the Homeland Security Department says it has authority to circumvent environmental reviews in this instance in the name of border security. Fourteen miles of the current fencing near San Diego is “no longer optimal for border patrol operations,” the department insists.

This case will be especially interesting because Trump and Curiel have some history. During the 2016 election, Curiel presided over a Trump University case in which several students sued over what they claimed was false advertising. Then-candidate Trump called Curiel a "hater" and suggested his Mexican heritage made him biased.

"We are building a wall," Trump told CNN's Jake Tapper at the time. "He's a Mexican. We're building a wall between here and Mexico."

He wanted Curiel to recuse himself.

The outrage was swift, even from Republicans. House Speaker Paul Ryan called Trump's remarks "the textbook definition of a racist comment."

The Trump University case was settled at $25 million, ten days after Trump won the election. As a result, nearly four thousand former students could get back about 90 percent of their money.

Two dozen members of the Congressional Hispanic Caucus have filed a brief in support of the court order over the border wall.