In a scathing critique claiming incumbent Sen. Barbara Boxer has made no significant impression on Washington, D.C., the editorial board at the San Francisco Chronicle on Sunday declined to offer an endorsement in California's heated Senate race.

Arguing that it could not support Republican challenger Carly Fiorina's policies even though it suspects she would be effective in Washington, the newspaper's editorial page said it is "extremely rare" that it would offer no recommendation on such an important race as this one, but "this is one necessary exception."

Boxer "has failed to distinguish herself during her 18 years in office. There is no reason to believe that another six-year term would bring anything but more of the same uninspired representation," the Chronicle's editors wrote.

"Her most famous moments on Capitol Hill have not been ones of legislative accomplishment, but of delivering partisan shots," the paper reads. 

The editorial notes that Boxer has previously "had the good fortune" of running against "inept, underfunded" or fringe opponents in the Senate race, but this time her opponent -- Fiorina -- "is proving to be articulate, well-funded and formidable." 

"It is a dismal choice between an ineffective advocate for causes we generally support and a potentially strong advocate for positions we oppose. Neither merits our endorsement for the U.S. Senate," the editors wrote.

The latest Los Angeles Times/USC poll out Sunday puts Boxer 8 points above Fiorina, 51-43 percent.

Click here to read the San Francisco Chronicle editorial.

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