"I do know that if in fact U.S. military or coalition forces feel that, in the execution of a target, that it's going to lead to exorbitant American or coalition forces losses, that we'll use proportional force rather than put young men and women's lives at risk."

In June 2002, U.S. officials say intelligence had revealed that Zarqawi and members of al-Qaida had set up a weapons lab at Kirma, in northern Iraq, producing deadly ricin and cyanide.

The Pentagon quickly drafted plans to attack the camp with cruise missiles and airstrikes and sent it to the White House, where, according to U.S. government sources, the plan was debated to death in the National Security Council.

“Here we had targets, we had opportunities, we had a country willing to support casualties, or risk casualties after 9/11 and we still didn’t do it,” said Michael O’Hanlon, military analyst with the Brookings Institution.

Four months later, intelligence showed Zarqawi was planning to use ricin in terrorist attacks in Europe.

The Pentagon drew up a second strike plan, and the White House again killed it. By then the administration had set its course for war with Iraq.

“People were more obsessed with developing the coalition to overthrow Saddam than to execute the president’s policy of preemption against terrorists,” according to terrorism expert and former National Security Council member Roger Cressey.

In January 2003, the threat turned real. Police in London arrested six terror suspects and discovered a ricin lab connected to the camp in Iraq.

The Pentagon drew up still another attack plan, and for the third time, the National Security Council killed it.

Military officials insist their case for attacking Zarqawi’s operation was airtight, but the administration feared destroying the terrorist camp in Iraq could undercut its case for war against Saddam.