Representative Bruce Braley (D., Iowa) has been relying on early voters to propel him to victory in the Iowa Senate race, but Republicans have deprived Democrats of that traditional strength.

For the first time ever, Republicans lead Democrats in terms of ballots cast by early voters.

“Today, cumulative Iowa registered Republican returns/early votes surpassed Democrats, to take a lead of 305 returned ballots,” Mark Stephenson of Cardinal Insights wrote Wednesday night in a memo for Republican Senate nominee Joni Ernst. “In 2010, the lead for Democrat returns at this point in the cycle was 16,426 ballots.”

Early voting in Iowa began on September 25, three days before Ernst turned in a strong performance in her first debate with Braley.

Iowa Republicans are so accustomed to losing among early voters that Jamie Johnson, a member of the state-party central committee, told me to assume that Braley’s lead was actually three points higher than the poll numbers show.

He doesn’t think that anymore. “The momentum in Iowa’s Senate race has completely shifted over the last three weeks,” Johnson says in a text message. “The astounding turnout of people on very short notice and the raw enthusiasm that we are seeing at Joni’s events resemble the closing days of Mike Huckabee’s and Rick Santorum’s Iowa Caucus victories, only it is more palpable.”