Along the southern California coast there are few opportunities to create new wetlands; hence, mitigators often propose to remodel existing wetlands to achieve greater value rather than offering to create new habitat. Restoration and/or mitigation plans have been proposed for about half the region's 29 coastal wetland systems, with debate over which objectives can be met and little ability to predict the cumulative result. I briefly summarize what is known of the historic functioning of southern California wetlands, and describe four specific mitigation case studies to document problems and concerns. There is an urgent need for wetland modifications to be guided by a regional wetland restoration plan, and I therefore propose a strategy to this end. Knowledge of the dilemma in southern California may help other regions avoid similar problems by developing landscape‐level approaches to habitat protection and restructuring before too much of the resource is lost.