A year ago, these groups seemed to be at the peak of their influence, needing only the Senate’s approval for a landmark climate-change bill. But they lost that fight, done in by the sluggish economy and opposition from business and fossil-fuel interests.

Now the groups are wondering how they can keep this loss from becoming a rout as their opponents press their advantage and try to undo the Obama administration’s climate efforts. At two events last week in Wisconsin, environmental groups seemed to be trying two strategies: defiance and pleading for sympathy.Neither one drew enough people to fill a high school gym.