White House senior adviser David Plouffe on Sunday elevated what is crystallizing into a central Obama campaign claim: Mitt Romney is building his campaign on lies.

“Right now their campaign is built on a tripod of lies,” he said on ABC’s “This Week.” “A welfare attack that is just absolutely untrue. The suggestion we’re raiding Medicare — absolutely untrue. And then this whole ‘we can build it’ nonsense.”

The remarks reflect Team Obama’s exasperation with the attacks from Romney and his surrogates that either misrepresent the facts or omit important context on issues at the heart of the election.