The current and former vice presidents of the United States sparred over terror policy Sunday on American television.  

Since leaving office a year ago, Dick Cheney has been one of President Barack Obama's strongest critics.  He has challenged the administration's commitment to fighting terror in numerous speeches and interviews.

Joe Biden says he is wrong.

"He either is misinformed or he is misinforming, but the facts are his assertions are not accurate," said Biden.

Biden told NBC's Meet the Press his predecessor is trying to rewrite history.  On ABC's This Week, Cheney defended his stance, adding now that he is out of office, he sees no reason to remain silent on matters of national security.

"I have the great freedom and luxury of speaking out, saying what I want to say and what I believe.  And I have not been discouraged from doing so," said Cheney.

It was an extraordinary public airing of differences between a current vice president of the United States and his predecessor.

When the White House learned Cheney would be on ABC, it offered Biden to two rival networks.  The NBC interview was recorded in advance.  After Cheney spoke on ABC, Biden got a live rebuttal on CBS's Face the Nation.

They sparred over the treatment of terror suspects, and the proper venues for terror trials.  Cheney accused the administration of downplaying the terrorist threat to America.

"I think that the biggest strategic threat to the United States faces today is the possibility of another 9/11 with a nuclear weapon or a biological agent of some kind," noted Cheney.  "And I think al-Qaida is out there even as we meet trying to figure out how to do that."

On Face the Nation, Biden said al-Qaida is well aware of the heightened security measures in place in the United States.  He said terrorists are focusing on smaller attacks, rather than the massive kind of strike seen on September 11, 2001.

"The reason why I do not think it is likely is because of all the resources we have put on this, considerably more than the last administration did, to see to it that it will not happen," he explained.

Biden and Cheney also clashed over U.S. policy toward Iran.  Biden said there has been significant progress in addressing the threat posed by Iran's nuclear program.  But Cheney said he is not sure the Obama administration will do what is necessary to keep Iran from developing nuclear weapons.

"I certainly would hope sanctions would work.  But I think they are most likely to work if you keep the military option on the table," Cheney said.

Cheney went on to defend the Bush administration's decision to go to war in Iraq.  But Biden countered that the Bush White House mishandled the conflict, and should have been more focused on fighting al-Qaida in Afghanistan.