The "phone tree," according to The Daily Beast on Wednesday, was one of several actions Buttigieg took to protect illegal immigrants in his town. Phone trees consist of an automated calling system that helps spread messages quickly and efficiently.
Those would presumably help alert immigrants to the type of surprise raids that resulted in nearly 700 arrests in Mississippi.
His approach to immigration came under legal scrutiny when Judicial Watch, a right-leaning organization, sued the city over a "Community Resident Card" program that Buttigieg reportedly developed with the help of La Casa, a left-wing, pro-immigration group.
The program allowed residents to open bank accounts, fill prescriptions, and use public services without fear that authorities would find out their immigration status. Buttigieg specifically partnered with local businesses on the program and directed utilities and other services to accept the cards as a valid form of identification.
Buttigieg was just one of many 2020 Democratic presidential candidates who sought to help immigrants avoid interactions with federal immigration enforcement.
On Monday, the administration prompted criticism by releasing a controversial rule that would limit green card recipients depending on whether they met a certain income threshold or relied on public assistance.
Trump has also leveled fierce criticism at "sanctuary cities" that refuse to cooperate with federal law enforcement on requests to continue detaining illegal immigrants. Buttigieg has blasted that type of cooperation as "conscription," although Indiana has banned "sanctuary cities" in the state.