NEW ORLEANS - Four conservative activists accused of trying to tamper with a senator's phones were just trying to record embarrassing undercover video of her staff ignoring phone calls from constituents angry that she supported a health-care overhaul, one of their attorneys said yesterday.

The four, including James O'Keefe, known for posing as a pimp and using a hidden camera to target the community-organizing group ACORN, were arrested Monday after targeting Democratic Sen. Mary Landrieu's office in a New Orleans federal building.

Lawyer J. Garrison Jordan denied that they were trying to disable or wiretap the phones in Landrieu's office.

"You're dealing with kids," he said. "I don't think they thought it through that far."

Instead, Jordan said, they hoped to get embarrassing video footage of Landrieu's staff handling constituent calls. Her office received complaints last month that callers opposed to her health-care stance could not get through.

Landrieu was not impressed with Jordan's explanation. "Attorneys are hired to spin for their clients," she said yesterday in an interview in Washington. "Good luck."

Protesters marched in front of Landrieu's office in Baton Rouge in December to criticize her support for Senate health-care legislation and complain that they could not get through on her office phones. Landrieu said at the time that her office received a high volume of calls.

"Our lines have been jammed for weeks, and I apologize," Landrieu said in an interview with the Advocate of Baton Rouge in December.

Jordan said his client, Robert Flanagan, the 24-year-old son of a federal prosecutor in Louisiana, did not intend to break the law when he went into the office posing as a telephone worker.

No matter their intentions, the four face the serious charge of entering federal property under false pretenses for the purpose of committing a felony, which carries up to 10 years in prison. They are free on $10,000 bail.

Investigators are aware of Jordan's explanation but are pressing ahead to see if that was indeed the men's motive, a senior federal law enforcement official said yesterday. The official spoke on condition of anonymity because the investigation is continuing.

Charged along with O'Keefe and Flanagan were Joseph Basel, 24, of Minnesota, and Stan Dai, 24, of the Washington area. The four are due back in court Feb. 12.

O'Keefe hinted last week that he had a new, high-profile stunt in the works. Four days before he was charged in connection with the Landrieu incident, he promised his audience at a conservative think tank's luncheon that they would be hearing about a project he was working on in New Orleans.