In September 2012, Hannah signed environmental activist Tom Weis' open letter calling on President Barack Obama and Governor Mitt Romney to withdraw their support for the construction of the southern leg of the Keystone XL pipeline, that would transport oil sands from Montana to Texas. Other signatories included climate scientist James Hansen and actors Sheryl Lee, Mariel Hemingway, and Ed Begley Jr.. On October 4, 2012, Hannah was arrested and jailed in Wood County, Texas, for criminal trespassing. She and a local landowner, 78-year-old Eleanor Fairchild, were arrested while protesting against the TransCanada Keystone XL oil sands pipeline by attempting to block heavy construction equipment. Although they were charged with trespassing, they were in fact protesting on Fairchild's land. On February 13, 2013, Hannah was arrested at the White House along with Robert F. Kennedy Jr. and Conor Kennedy during a climate change protest against the proposed Keystone Pipeline.