The next time Islamist terrorists attack us it could be with a nuclear weapon. By saying that, am I “fear mongering”? If so, I’m in good company. Graham Allison is a Harvard professor who served with distinction in the Defense Department under both Reagan and Clinton. He wrote a book in 2004 arguing that “on the current course, nuclear terrorism is inevitable.”

There has been no change of course since – on the contrary. Ashton B. Carter, co-director of the Preventive Defense Project at Harvard, said recently that the threat of nuclear terrorism has been increasing due to Iranian and North Korean proliferation and the failure to secure Russia's nuclear arsenal following the Cold War. The probability of a nuclear attack on an American city, he believes, is now “almost surely larger than it was five years ago.”

Gary Anthony Ackerman, Research Director of the National Consortium for the Study of Terrorism and Responses to Terrorism, also recently told Congress that “the prospect of terrorists detonating a nuclear device on American soil sometime within the next quarter-century is real and growing.”

And Cham D. Dallas, who directs the Institute for Health Management and Mass Destruction Defense at the University of Georgia, says flatly: “It’s inevitable.” Testifying before a Senate hearing this month, he added: “I think it's wistful to think that it won't happen by 20 years."

Should a 10-kiloton nuclear bomb explode near the White House, Dallas estimates that 100,000 people would be killed. A radioactive plume would lethally contaminate thousands more. In a densely populated city such as New York or Chicago, a similar blast would result in a death toll perhaps eight times that high.

Charles Allen, Undersecretary for Intelligence and Analysis for the Department of Homeland Security, has said there is no question that Islamist terrorist groups are seeking nuclear materials. But the intelligence community, he added, is “less certain about terrorists' capability to acquire or develop a nuclear device.”

Could the intelligence community be more certain? Yes, our spies could do more to increase our chances of detecting - -- and preventing – terrorist attacks of all varieties. But they are being denied the tools. The most notable example: The law that gave America’s intelligence agencies the authority to freely monitor the communications of foreign terrorists abroad expired in February.

A bill to restore that authority passed the Senate by a solidly bipartisan 68-to-29 majority. A bipartisan majority in the House would almost certainly vote in favor of the same measure but Speaker Nancy Pelosi – for more than two months – has used the power of her office to stop members from casting their votes yea or nay.

Why would she do something so irresponsible? Groups on the left, important to the Democrats in this election season, demand that foreign terrorists abroad be given the same privacy protections enjoyed by American citizens here at home.

This policy may already have cost American lives. In at least one instance, U.S. officials labored for nearly 10 hours to get legal approval necessary to conduct wiretaps to help them locate three American soldiers kidnapped by al-Qaeda combatants in Iraq. The soldiers were not successfully rescued.

"We are extending Fourth Amendment (constitutional) rights to a terrorist foreigner ... who's captured a U.S. soldier," Director of National Intelligence Michael McConnell complained to a congressional committee during a legislative battle over this same issue last year.

Also in the mix: Trial lawyers are suing telecommunications companies that cooperated with intelligence officials immediately after 9/11/01, allowing them to “mine” data for patterns of terrorist activity. If the trial lawyers – the biggest donors to Democrats – succeed, they will reap billions of dollars. They also will teach the private sector never again to assist government efforts to identify terrorists. The Senate bill would protect the telecoms from these laws suits.

Almost two dozen moderate Democratic House members sent Pelosi a letter saying that until this measure is passed, America’s national security will be “at undue risk.” But that was months ago. Since then, with few exceptions, Democrats have been keeping their mouths shut.

Is worrying about nuclear terrorism fear mongering? After the suicide-bombing of the U.S. Marine barracks in Beirut in 1983, and again after the truck-bombing of the World Trade Center in 1993, most politicians exhibited not fear but complacency. They did nothing serious to anticipate or avert the next terrorist attacks. The consequence was the atrocity of 9/11/01.

Nancy Pelosi and those following her lead appear to have learned nothing over the years since.