In an unusual step, the executive director of the Democratic Senatorial Campaign Committee on Monday issued a rebuttal the famed statistician’s prediction – made a day earlier – that Republicans were a “slight favorite” to retake the Senate. Silver was wrong in 2012, the political committee’s Guy Cecil wrote in a memo, and he’ll be wrong again in 2014.

“In fact, in August of 2012 Silver forecasted a 61 percent likelihood that Republicans would pick up enough seats to claim the majority,” Cecil said. “Three months later Democrats went on to win 55 seats.”

The DSCC memo took pains to compliment Silver, saying his work at the newly launched FiveThirtyEight was “groundbreaking.” And the group’s main critique – that Silver’s model relies on a smattering of haphazard early polling in battleground states – is one that he himself acknowledges is a limitation.

But the comprehensive pushback from Cecil, the powerful committee’s key staffer, is a testament both to the influence Silver wields and the sensitivity of Senate Democrats to the perception they’re losing their grip on the upper chamber. Other outlets have suggested similar odds on the Senate, but none have earned this kind of rebuttal.