The White House has cited supportive statements from the World Wildlife Fund, the Nature Conservancy, the Humane Society, the Wildlife Conservation Society, Defenders of Wildlife, International Fund for Animal Welfare, World Animal Protection and other environmental groups in favor of the TPP. The Peterson Institute for International Economics argues that the TPP is "the most environmentally friendly trade deal ever negotiated." In regards to ISDS, PIIE analysts note that there is little evidence of constraints on environmental policies resulting from ISDS litigation.