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Liz Cheney, Vice President Dick Cheney's daughter and a former Bush administration official, on Monday accused Vice President Biden of downplaying the threat from Al Qaeda and suggested the Obama administration isn't doing everything in its power to stop terror.

Cheney came to her father's defense Monday after Biden said the former vice president is "misinformed or is misinforming" the country about the Obama administration's unnamed War on Terror.

Liz Cheney repeated her father's contention -- backed up by a study issued last week by Harvard's Kennedy school of Government -- that Al Qaeda is trying "very hard" to get and use a weapon of mass destruction.

"There's very strong concern that still remains that Al Qaeda is working very hard to try to obtain weapons of mass destruction and Al Qaeda armed with any nuclear or biological weapon is clearly one of the gravest threats we face," Liz Cheney said.

"The notion that this White House and this administration is minimizing that possibility makes you very concerned, I think has to make us very concerned about whether or not they are doing everything in their power to prevent it," she added.

Cheney followed her father, who on Sunday said that Biden's claim that another Sept. 11 attack is unlikely is "dead wrong."

"I think the biggest strategic threat the United States faces today is the possibility of another 9/11 with a nuclear weapon or a biological agent of some kind, and I think Al Qaeda is out there even as we meet trying to figure out how to do that," he told ABC's "This Week."

In a separate interview that aired Sunday, Biden said that Al Qaeda is on the run because of the efforts of the Obama administration

"The president of the United States said in the State of the Union we're at war with Al Qaeda," Biden told NBC's "Meet the Press."

"We're pursuing that war with a vigor like it's never been seen. We've eliminated 12 of the top 20 people, we have taken out 100 of their associates, we are making -- we've sent them under ground. They are, in fact, not able to do anything remotely like they were in the past. They are on the run. I don't know where Dick Cheney has been. Look, it's one thing, again, to criticize. It's another thing to sort of re-write history. What is he talking about?" Biden continued.

Liz Cheney said it's no surprise that her father or others would question whether the administration is doing it all it can when the country has no detention policy that assigns a designated holding facility for captured Al Qaeda leaders nor does it have an effective interrogation policy.

She added that the drone program being used to assassinate leaders is important, but it's also important to capture some senior Al Qaeda leaders in order to interrogate them.

"There's simply no way you can say that he president is using every tool at his disposal to fight and win this war without being able to get the intelligence you need actually to defeat Al Qaeda," she said.

Biden has a "famously tenuous relationship to reality, frankly," she added.

Liz Cheney said her father is speaking up because he is very concerned about the unraveling of Bush administration security policies, particularly the decisions to close Guantanamo Bay and try Khalid Sheik Mohammad and other Sept. 11 suspects in a federal court, and that impact on the War on Terror.

You Decide: Is Biden's declaration of no more Sept. 11 attacks similar to saying "mission accomplished"?