At Barnard College, a temporary wall erected around the construction site of a new multimilliondollar building has become the center of political discussion on a campus known for staying out of the fray.

With the blessing of the administration, Barnard students and faculty have transformed the wall into a physical blog, writing opinions about President Ahmadinejad’s visit to Columbia University, opposition to Columbia’s plans to expand into Manhattanville, the war in Iraq, and even advertising events such as a “breast” cupcake bake sale to raise money for the American Cancer Society.

“It’s become the focal point of anger on campus,” a sophomore studying political economics at Barnard, Sara Horvath, said. “Right now, people are writing about the racial slurs at Columbia, and their anger about the wall and the construction project itself.”

Transforming a construction wall, which will block the main walkway on campus for two years while a 70,000-square-foot campus center rises from the ground, into a venting space for students is Barnard’s effort to turn a disruptive situation into a space for a productive exchange of ideas.

The wall is wrapped in a white vinyl covering featuring supersize silhouettes of Barnard students photographed by an alumnus, artist Katherine Wolkoff.

A few months after the wall was erected, the covering now has several layers of conversation, and the dialogue is growing more heated as more students use the space to react anonymously to campus and world events.

“Most Americans are now against the war in Iraq because we’re losing,” one student scribbled on the wall on Sunday afternoon. “If we were winning their cries would be different.” Another student had used red spray paint to write: “Are we bigots? Hate does not exist in a vacuum.”

An introductory painting class in Barnard’s visual arts department is planning to incorporate the wall into a class assignment, and students who have studied abroad in Ghana and India are planning to use the wall as a gallery space to display their photographs.

“People don’t like the wall because it’s huge and annoying,” a freshman dressed in an oversized T-shirt that read “I hated Bush before it was cool,” Maggie Astor, said. “Turning it into a place where students can respond to each other makes the best of an annoying situation.”

While racist and anti-Semitic graffiti has been found scrawled in several bathroom stalls on the campus of Columbia over the past few months, the dialogue on the wall at Barnard has so far been respectful, students said.

“It’s a less politically active and smaller student body,” Ms. Horvath said. “If someone wants to grab attention, they’re probably going to do something on Columbia’s campus, not here.”