555 U.S. 7, 20 (2008)
The United States Navy planned to conduct fourteen Composite Training Unit Exercises and Joint Tactical Force Exercises in the Southern California Operating Area between 2007 and 2009.1 These exercises were part of certifying strike groups for overseas deployment.2 They required extensive use of mid-frequency active sonar, the only proven method for detecting modern diesel-electric submarines operating on battery power.3 The Navy had conducted similar training with mid-frequency active sonar in the same waters for forty years.4
In February 2007 the Navy issued a 293-page environmental assessment concluding that the exercises would not significantly affect the environment.5 The assessment predicted eight Level A harassments of common dolphins each year.6 It also predicted 274 Level B harassments of beaked whales per year.7 The assessment stated that even these effects could be avoided through the Navy's voluntary mitigation measures.8
The Natural Resources Defense Council and other environmental plaintiffs filed suit in the United States District Court for the Central District of California.9 They alleged that the Navy had violated the National Environmental Policy Act by failing to prepare a full environmental impact statement.10 The district court granted a preliminary injunction barring all use of mid-frequency active sonar during the remaining exercises.11
The President granted the Navy an exemption from the Coastal Zone Management Act. The Council on Environmental Quality approved alternative arrangements under the National Environmental Policy Act.12 The district court then modified the injunction to permit training subject to six additional mitigation measures.13 These measures included a mandatory 2,200-yard shutdown zone around any detected marine mammal and a requirement to power down sonar by six decibels during significant surface ducting conditions.14
The Court of Appeals for the Ninth Circuit affirmed the modified preliminary injunction.15 The Navy filed an emergency application in the Supreme Court seeking to vacate the injunction.16 The Court granted certiorari.17
Whether the district court and court of appeals applied an incorrect standard by requiring only a possibility rather than a likelihood of irreparable harm to support a preliminary injunction?18
A plaintiff seeking a preliminary injunction must establish that he is likely to succeed on the merits, that he is likely to suffer irreparable harm in the absence of preliminary relief, that the balance of equities tips in his favor, and that an injunction is in the public interest.19 The standard for irreparable harm is likelihood, not possibility.20
Yes. The District Court and the Ninth Circuit applied an incorrect standard for determining whether NRDC had demonstrated a likelihood of irreparable injury.21 The lower courts held that a plaintiff can demonstrate irreparable injury by showing only a possibility of irreparable harm.22 That standard is too lenient.23
The correct standard requires plaintiffs seeking preliminary relief to demonstrate that irreparable injury is likely in the absence of an injunction.24 The Navy has conducted similar exercises for forty years without documented proof of harm to marine mammals.25 The environmental assessment predicted only limited harassments that could be avoided through mitigation measures.26
The district court and court of appeals applied an incorrect standard by requiring only a possibility rather than a likelihood of irreparable harm to support a preliminary injunction.27
Related opinions on this issue
Joined by Justice Souter
Justice Ginsburg dissented on the standard for determining whether NRDC had demonstrated a likelihood of irreparable injury.28 She maintained that the possibility standard has been widely accepted in the lower courts and should not be discarded in this case.29 She argued that courts of equity have long exercised discretion to grant injunctions based on a balancing of hardships, even when the plaintiff's harm had not been shown to be certain.30
Justice Ginsburg viewed the majority's requirement of a likelihood showing as a departure from traditional equitable practice that had allowed relief based on a balancing of hardships without demanding certainty of harm.31 She would have affirmed the judgment of the Court of Appeals on this ground.32
Whether the record established a likelihood of irreparable injury to marine mammals from the Navy's use of mid-frequency active sonar during the planned training exercises?33
NRDC has not carried its burden of establishing a likelihood of irreparable injury.34 The record contains no evidence that the Navy's training exercises have harmed marine mammals in the Southern California Operating Area.35 The Navy has conducted similar exercises for forty years without documented proof of harm to marine mammals.
No. The record contains no evidence that the Navy's training exercises have harmed marine mammals in the Southern California Operating Area.36 The Navy has conducted similar exercises for forty years without documented proof of harm to marine mammals. The District Court relied on studies showing that marine mammals may be affected by mid-frequency active sonar at levels that could cause temporary hearing loss or behavioral disruption.37 Those studies do not establish that the Navy's exercises are likely to cause harm.38
The environmental assessment predicted limited harassments.39 The established facts confirm no actual documented injury occurred over four decades of training.40
The record did not establish a likelihood of irreparable injury to marine mammals from the Navy's use of mid-frequency active sonar during the planned training exercises.41
Related opinions on this issue
Joined by Justice Stevens
Justice Breyer concurred in the judgment vacating the injunction but noted uncertainty in the harm figures from the environmental assessment.42 He observed that the raw numbers of predicted harassments seem large.43 The parties dispute their meaning.44
The Navy argues the estimates err on the side of caution.45 No injured marine mammal has ever been found despite forty years of exercises.46 Justice Breyer emphasized that the Navy's affidavits made a strong case that the two additional conditions would seriously interfere with necessary defense training.47
He concluded that the District Court did not adequately explain its rejection of those contentions.48
Whether the balance of equities and the public interest favored the Navy's interest in conducting realistic antisubmarine warfare training exercises over the plaintiffs' environmental interests?49
Even if NRDC could show a likelihood of irreparable injury, the balance of equities and the public interest tip strongly in favor of the Navy.50 The Navy's training exercises serve a vital national interest in naval preparedness.51 The President has determined that the exercises are essential to national security.52
Yes. The Navy's training exercises serve a vital national interest in naval preparedness. The President has determined that the exercises are essential to national security. The injunction would force the Navy to use less effective training methods.53
This would impair the ability of strike groups to detect enemy submarines.54 It would thereby place the lives of sailors and marines at risk.55 The plaintiffs' interests in observing and studying marine mammals are outweighed by these national security concerns.56 The established facts show the exercises are mission-critical for certification and deployment.57
The balance of equities and the public interest favored the Navy's interest in conducting realistic antisubmarine warfare training exercises over the plaintiffs' environmental interests.58
Related opinions on this issue
Joined by Justice Souter
Justice Ginsburg would have affirmed the judgment of the Court of Appeals.59 She maintained that the District Court carefully balanced the equities and concluded that the balance favored some limitation on the Navy's use of sonar to protect marine mammals.60 She argued that conclusion is entitled to deference.61
The Navy has used similar mitigation measures in the past without significant impairment of its training.62 Justice Ginsburg viewed the majority's decision to vacate the injunction as premature because the Navy had not demonstrated irreparable harm from complying with the mitigation measures.63 She would have upheld the district court's equitable balancing.64
Joined by Justice Stevens
Justice Breyer would vacate the two challenged conditions but keep the remaining mitigation measures in place until the EIS is complete.65 He concluded that the record lacks adequate support for imposing the 2,200-yard shutdown zone and the surface ducting power-down requirement.66 The District Court did not explain why it rejected the Navy's affidavit-supported contentions that those measures would seriously interfere with necessary defense training.67
Justice Breyer noted that the Navy's affidavits detailed the cascading negative effects on training effectiveness and strike group certification.68 He determined that the modified conditions from the Court of Appeals stay order should remain until the EIS is finished.69