The provocative characterization Sunday came just days after bin Laden attracted international attention with the release of a video in which he ridicules Mr. Bush about the Iraq war and reminds the world that he has not been captured.
Ahead of the sixth anniversary of the Sept. 11 terrorist strikes, White House aide Frances Fragos Townsend made a clear attempt to diminish the influence - or the perception - of the man who masterminded those attacks.
"This is about the best he can do," Townsend, the White House Homeland Security Advisor, said of bin Laden. "This is a man on a run, from a cave, who's virtually impotent other than these tapes."
In appearances on two Sunday talk shows, she used the "virtually impotent" reference both times, suggesting the language was chosen with careful purpose.
"We know that al Qaeda is still determined to attack, and we take it seriously," Townsend said. "But this tape appears to be nothing more than threats. It's propaganda on their part."
Townsend was considerably more direct than even Mr. Bush in rebuking bin Laden. The U.S. president responded to bin Laden's tape last week by saying it was a reminder that the world is dangerous and that Iraq is part of the war against extremists. He never identified bin Laden by name.
The consensus of the top U.S. intelligence analysts is that bin Laden's terrorist network is anything but impotent.
Terrorism experts say the network is regrouping in the lawless Pakistan-Afghanistan border region. The latest National Intelligence Estimate says al Qaeda is growing in strength, intensifying its efforts to put operatives in the United States and plotting against U.S. targets that will cause massive casualties. The United States is in a "heightened threat environment" and al Qaeda is the most serious threat, the analysts found.
The tape was the first time bin Laden had appeared in a new video since 2004. In the recording, bin Laden tells Americans they should convert to Islam if they want the war in Iraq to end. He makes no overt threats and does not directly call for attacks.
What he is trying to say is that he is under no pressure from the Americans. The Americans are failing in their effort to kill him, and in their effort to destroy al Qaeda."
"While he may be physically contained, his influence is not bounded by any physical barriers," said Thomas Sanderson, an authority on terrorism at the Center for Strategic and International Studies.
"Obviously, in a sense, it does not matter that we've got him trapped in a cave. He has sent forth enough messages to incite violence worldwide against us," he said in an interview Sunday.