The Washington Post endorsed Mayor Adrian Fenty in the Democratic primary for mayor.

The endorsement is a blow to D.C. Council Chairman Vincent Gray, a GW alumnus and Fenty’s main opponent in the race.

According to the editorial, the District has made great strides forward as a result of Fenty’s leadership over the past four years, adding that Gray’s campaign is based on mudslinging against Fenty without any substantive ideas to better the city.

“Four years ago, Mr. Fenty laid out a clear and well-thought-out agenda; he then proceeded, to a degree unusual at any level of government, to do precisely what he had said he would do,” said the editorial, citing Gray’s plans as “alarmingly vague.”

In response, Gray tweeted that he was not surprised by the Post’s endorsement of Fenty.

“Fortunately voters decide elections, not editorial boards. We’ll take our chances,” the tweet said. “But even the Post talked about Fenty’s ‘secrecy,’ ‘pathological unwillingness’ to listen to others and his ‘suspect contracts to friends,'” a following tweet said.

The primary election is scheduled for Sept. 14.