"We believe that your re-election to the U.S. House of Representatives will help produce sustained economic growth, help create jobs, and get our country back on track," Chamber of Commerce President Thomas Donohue wrote in a letter to Peters on Aug. 29, according to the San Diego Union-Tribune on Wednesday. "We will encourage the business community to vigorously support your candidacy."
The endorsement is welcome news for Peters (pictured) who is in a tight race against former San Diego City Councilman Carl DeMaio (R).
"We're not surprised that a special interest group in D.C. is trying to protect members of Congress —they like the system the way it is. They know Carl DeMaio is coming to end the perks of this crowd," DeMaio spokesman Dave McCulloch told the San Diego newspaper.
Rob Engstrom, the national political director for the Chamber, shot back that the DeMaio campaign tried to get the group's endorsement.
.@carldemaio spox needs to get facts straight. The campaign actively sought our endorsement. Sour grapes. http://t.co/JFJb5uygsU
— Rob Engstrom (@RobEngstrom) September 3, 2014
It's also a rare move for the Chamber of Commerce which usually backs establishment-aligned Republicans. In 2012, the Union Tribune noted, the group backed GOP Rep. Brian Bilbray over Peters.
Peters also voted 69 percent of the time on legislation supported by the organization in 2013, according to the Chamber. DeMaio has been running as a moderate but Peters' campaign has tried to portray him as a hard-right conservative.
Earlier in the year TPM flagged a dustup between DeMaio and National Journal when the publication accused the candidate of plagiarizing a report on pension double-dipping.
This story has been updated.