Congressional Republicans are resisting entreaties from Democrats to support a federal clean electricity mandate, widening the gulf between the two parties and showing the limits on what Republicans are willing to stomach as they shift toward saying that climate change is a problem worth addressing.

Supporters view so-called clean electricity standards as more likely to attract bipartisan support than carbon taxes, which the GOP also resists, because the resulting higher energy costs would not be as obvious to people. Clean standards are also more narrowly tailored than carbon taxes, applying only to electricity generation, meaning high-emitting sectors such as transportation would not be addressed.