Capitol Hill's most powerful Republicans say advocates who have been discussing a carbon tax behind closed doors are wasting their breath.

House Speaker John Boehner (R-Ohio) and Senate Minority Leader Mitch McConnell (R-Ky.), speaking through aides, have stated their opposition to the concept in recent days.

Boehner spokesman Michael Steel had a one-word answer when asked, on Friday, whether the Speaker would ever consider a carbon tax to help address climate change and the deficit: "No."

Similarly, McConnell spokesman John Ashbrook said Monday that "Leader McConnell opposes a national energy tax."