Gov. Kristi Noem (R) recently signed a package of laws to crack down on anti-pipeline demonstrations — a move the tribe says infringes on free speech.
Environmentalists blast Trump for "contempt" for law and the planet.
The Trump administration must carry out a valid environmental review before the project can proceed, rules a U.S. District Court judge in Montana.
But the president's tightening grip on the courts could change his administration's fortunes.
Your Energy, an industry front group, claims to have recruited 10,000 people to its cause of battling pipeline protesters.
The congressman urged state officials to think about climate change, pollution and Native American rights.
Nebraska state regulators voted to approve the pipeline, but rejected the proposed route, making its future uncertain.
The spill this week is the largest in the existing pipeline's history.
"It’s not too late to protect Nebraska’s families, farms, and communities from paying the same price,” a conservation group says.
"This type of fossil fuel should not be happening."
Environmental groups allege Trump administration approval of the project broke the law.