Maryland Gov. Larry Hogan, left, and Democratic gubernatorial nominee Ben Jealous. (Pete Marovich for The Post and AP)

A 1,418-page opposition research report on Republican Gov. Larry Hogan was made public last week by the Democratic Governors Association, the latest move by Democrats to attack Hogan’s reelection bid.

Normally, opposition reports are closely guarded documents used by campaigns to create talking points and attack ads. But Doug Thornell, a Democratic strategist not involved in the Maryland gubernatorial race, said Republicans and Democrats sometimes make such research available for various reasons, including so that independent expenditure campaigns — which can support candidates but may not coordinate with them — can access the information.

“It’s pretty commonplace in campaigning these days,” Thornell said.

Melissa Miller, a DGA spokeswoman, said the association wanted voters to see its research firsthand. It posted the report, which was done by Spiros Consulting, to its website, HoganBrokenPromises.com, on Wednesday.

The document, which was first reported by the Daily Record, offers a deep dive into Hogan’s personal, professional and political life.

“The DGA intends to hold Governor Hogan accountable for his record of breaking promises to Maryland,” Miller said in an email.

With a little more than 90 days left until Election Day, it remains unclear what role the DGA, which asks for contributions on the website, will play in Maryland. The Republican Governors Association started airing attack ads against Democratic gubernatorial nominee Ben Jealous last month.

Under election law, an independent expenditure group cannot communicate with a campaign. By placing the opposition research in the public domain, the independent expenditure group is able to use the information.

Jerusalem Demsas, a spokeswoman for the Jealous campaign, and Fabion Seaton, a spokesman for the state Democratic Party, referred all calls to the DGA.

According to campaign finance reports, Jealous has paid Spiros $70,000 in consulting fees over the past year. But Demsas said that money did not go toward the opposition research report.

Miller said the DGA funded the research.

The report includes information about Hogan’s positions on social and economic issues, as well as details about his personal likes and dislikes.

A large portion is devoted to past news articles.

Scott Sloofman, Hogan’s campaign spokesman, said the publication of the report — which he dismissed as “recycled opposition research from their failed 2014 attacks against Larry Hogan” — makes Democrats appear desperate.

“The DGA is effectively telling Ben Jealous, ‘Good luck, you’re on your own,’ ” Sloofman said.