DOVER, Del. — A group of young women claim they were ordered to leave a book signing featuring Sen. Rick Santorum because of their political views.

The federal lawsuit, filed Tuesday by the American Civil Liberties Union, argues that the women’s free speech rights were violated at the event last August. It says two of the women were arrested for trespassing and three others were threatened with arrest.

The suit names a Delaware state trooper and one of the Pennsylvania lawmaker’s representatives.

According to the lawsuit, the women went to a Barnes & Noble store in Wilmington to challenge Santorum at an event advertised as a signing and discussion of his book, “It Takes a Family.”

The women were ordered to leave by a state trooper hired to provide security after a member of Santorum’s promotional team overheard them talking before the senator arrived, according to the suit. When two of the women asked why they were being ejected, they were arrested, the suit say.

“The trooper denied these women their right to share their views with an elected official,” said Julia Graff, attorney for the Delaware ACLU, which sued along with the Pennsylvania ACLU.

Named as defendants were State Police Sgt. Mark DiJiacomo and the Santorum representative, identified only as “Jane Doe.”

DiJiacomo declined to comment, according to a state police spokesman.

Santorum spokesman Robert Traynham referred calls to the Intercollegiate Studies Institute, the think tank that published the book. The institute said it had no comment on the lawsuit.

Miriam Rocek, 20, is among the plaintiffs. “We think it’s outrageous that we were ejected simply because someone thought that we were going to express a dissenting opinion,” she said in a statement.

Santorum, the Senate’s No. 3 Republican, is embroiled in a tough re-election fight against Pennsylvania state Treasurer Bob Casey, a Democrat.

Some see Santorum’s book as a GOP response to Sen. Hillary Rodham Clinton’s “It Takes a Village.”

It argues, among other things, that stay-at-home mothers have been targeted by “radical feminism’s misogynistic crusade to make working outside the home the only marker of social value and self-respect.”