As court-appointed counsel for a death-row inmate, he presented the issue of whether a federal court may stay a section 2254 habeas corpus petition which included exhausted and unexhausted claims.

[7] The American Bar Association Standing Committee on the Judicial Nominations voted unanimously to rate Lange as "well qualified."

[10] On June 2, 2021, Lange ruled against South Dakota Governor Kristi Noem's efforts to have fireworks at Mount Rushmore, finding four of the five reasons given by the National Park Service and Department of the Interior Secretary Deb Haaland were valid.

[11] In March 2020, Lange interpreted the 1868 Treaty of Fort Laramie in light of congressional enactments and the federal government's trust obligation to American Indian tribes to require the federal government to provide the Rosebud Sioux Tribe with "competent physician-led health care" in a suit that followed the Indian Health Services having close the emergency department of the lone medical facility on the reservation.

[15] In April 2020, Lange issued a 106-page decision finding that five of six plaintiffs who had been forcibly catheterized at the direction of South Dakota law enforcement had viable claims for violation of their Fourth Amendment protections against unreasonable searches and seizures.

[17] Lange's criminal case load is the highest among federal judges for Native American defendants and violent crime from reservations.