Democrats who worry that war with Iraq will distract from, if not undermine, the war on terror must have been relieved by the weekend capture of Khalid Shaik Mohammed, a top operative in the terrorist Al Qaeda network.

"It was a coup that we were able to capture the No. 3 person. That is a significant, significant, significant happening," Sen. Joe Biden, D-Del., said Monday.

Biden, the ranking Democrat on the Senate Foreign Relations Committee, backs disarming Iraqi leader Saddam Hussein, but months ago he became one of the first in his party to argue that such an action would detract from the hunt for Al Qaeda.

In New York Monday, in what was billed a major foreign policy speech, Biden left out several lines that he had written before this weekend's bust in Pakistan.

Included in the omission was part of the original text, which stated: "The president has argued that confronting Iraq will not detract from our unfinished war against terrorism. I pray he's right, but I am afraid we've lost our focus."

Another line that was dropped said: "I lament the fact that while I support eliminating weapons of mass destruction, we've chosen Saddam over Usama."

Biden is well-known for changing his prepared remarks during delivery, and aides say his omission of any particular passage during Monday's speech was not deliberate.

The arrest of Usama bin Laden's operations chief is not likely to halt Democratic criticism of the Bush administration's handling of the war on terror or Iraq. It did appear to change Biden's speech, however.

But he didn't leave out accusations that President Bush has mishandled all manner of international affairs. After his remarks, though, Biden suggested that the weekend arrest showed that the U.S. is able to deal with Iraq and Al Qaeda simultaneously.

"It's a very significant breakthrough and it demonstrates that we're doing both and trying to do both. The real question is could we make even more progress if we had stayed focused on Al Qaeda?"

Biden also argued that pressuring the international community, and in particular Arab and Muslim nations, to support a war in Iraq may alienate them and cost the U.S their support in the fight against terrorism.

"What worries me the most is that we are making it difficult to get the kind of cooperation that we need," he said.

Biden's concern is real, but may not amount to much. For instance, Pakistan, a nation with no shortage of Islamist radicals, is under pressure to back war with Iraq and has been instrumental in capturing many of the most senior Al Qaeda operatives to date.

Fox News' Carl Cameron contributed to this report.