The American Civil Liberties Union is seeking to put pressure on Mitt Romney with a white paper and a new ad campaign at the presumptive GOP nominee’s three homes, as well as in Boston and Washington, D.C.

Former Massachusetts governor Mitt Romney. (Mario Tama/Getty Images)

Four of the ads will be displayed for one week on trucks parked in the District and outside Romney’s homes in Massachusetts, California and New Hampshire. Another ad will be placed on a stationary billboard outside Boston’s Logan Airport for the month of June. Images of the billboards were provided to The Washington Post by the ACLU.

The ad campaign is geared toward highlighting Romney’s 1994 Senate and 2002 gubernatorial campaigns, during which the presumptive GOP nominee was in alignment with the ACLU on key issues including gay and reproductive rights and immigration reform, the civil liberties group contends.

ACLU executive director Anthony Romero said the organization aims to use the ad campaign and its six-page white paper (pdf) to call into question Romney’s “core beliefs” in those three areas.

The group has never endorsed a presidential candidate in its nine-decade-long history. And Romero argued that while Romney has a “checkered history” on civil liberties, President Obama has “broken more than his share of campaign promises” on matters ranging from the National Defense Authorization Act to the continued use of the military prison at Guantanamo Bay, Cuba.

“President Obama hasn’t turned out to be the civil libertarian we thought. And maybe Gov. Romney isn’t the conservative we fear,” he said.

The white paper and images of the billboards are expected to be released by the group later Tuesday morning.