Forrest was a key expert witness for the plaintiffs in the 2005 Kitzmiller v. Dover Area School District trial. The defendants were represented by the Thomas More Law Center, a conservative Christian, not-for-profit law center whose motto is "The Sword and the Shield for People of Faith". After Forrest had been deposed, the TMLC tried but failed to have her stopped from testifying. In a motion to have her removed as a witness, they described her as "little more than a conspiracy theorist and a web-surfing, 'cyber-stalker' of the Discovery Institute...." Judge Jones denied the motion and Forrest's testimony began on October 5. According to Forrest, after the TMLC's attempt to exclude her as a witness had failed, and only a few days before she would be testifying, the Discovery Institute attempted to publicly ridicule her on their website. She wrote: During her testimony the defense lawyers again asked the court to exclude Forrest from testifying as expert witness. Judge Jones allowed them to present their case for dismissing her and then denied their request. Forrest would go on to testify on the religious origins and nature of the intelligent design movement, the wedge document, and also demonstrated that the drafts of the textbook at the center of the court case, Of Pandas and People, substituted terms such as "intelligent design" and "intelligent designer" in place of "creationism" and "creator" in an attempt to circumvent the ruling in Edwards v. Aguillard which determined that teaching creationism in public schools violated the Establishment Clause of the United States constitution. Her testimony had a significant impact on Judge Jones's decision. A year after the ruling, Forrest commented in a telephone interview "It was very clear to everyone who followed the case that intelligent design is not science. The Discovery Institute has been trying for years to foment a court case. And they finally got one dropped in their laps and what was ironic is they didn't want it. They knew what this case would do to them."
''Synthese'' essay
An essay by Forrest, "The non-epistemology of intelligent design: its implications for public policy", was published online in March 2009 as part of a special issue of the journal Synthese. The issue was titled "Evolution and Its Rivals" and was guest edited by Glenn Branch and James H. Fetzer, the latter a former editor of Synthese. Forrest's essay strongly criticized philosopher Francis J. Beckwith, noting that he had "no formal credentials as a constitutional scholar" to justify his stances on issues regarding the separation of church and state and connected Beckwith and other advocates of intelligent design to Christian Reconstructionism. Following complaints from Beckwith and others mentioned in the issue, the regular editors of Synthese, Johan van Benthem, Vincent F. Hendricks, and John F. Symons, included an editorial statement in the print version of the special issue, published in January 2011, which criticized the tone of some of the papers in that issue. The note was perceived as directed at Forrest's essay and drew angry denunciations from the guest editors, who were not consulted about the statement, and other critics. At least one philosopher has withdrawn a paper from Synthese as a result.
Forrest worked with Zack Kopplin and helped begin the campaign to repeal the Louisiana Science Education Act law. The repeal effort, SB70 of 2011, failed in the Senate Education Committee by a 5–1 vote. The repeal effort, SB374 of 2012, also failed in the Senate Education Committee by a 2–1 effort.
Public speaking
Forrest has appeared in the media, including PBS. She was the featured speaker for Southeastern Louisiana University's Linus A. Sims Memorial Library commemoration of the 150th anniversary of the publication of Darwin's Origin of Species on 23 April 2009.
