This CIFOR Occasional Paper presents research results on challenges experienced by proponents in their efforts to establish REDD+ subnational initiatives in Brazil, Peru, Cameroon, Tanzania, Indonesia, and Vietnam. On the basis of in-depth interviews with 23 organizations collaborating in CIFOR's Global Comparative Study on REDD+, it was found that the biggest challenges are tenure and the (currently) disadvantageous economics of REDD+. The study observes several patterns connected with these challenges. Performance-based conditional incentives are judged important but are not as central as once envisioned. Although most organizations are forging ahead with REDD+ in spite of the difficulties, some are drifting away from the label "REDD+." Most of the organizations rely heavily on "integrated conservation and development" as a mode of operation, which enables them to move forward in anticipation of more favorable conditions for REDD+, but raises questions about whether REDD+ will fulfill its promise as an innovative and more effective form of conservation. The study proposes some options for overcoming the main challenges, and observes that there are some grounds for hope that REDD+ can eventually turn the corner and fulfill its potential for greatly reducing deforestation and forest-based carbon emissions.