After the September 11th terrorist attacks on the United States in 2001, President Bush declared a war on terrorism. Since then, various experts have called the struggle to defeat Islamist militants worldwide the global war on terror, the clash of civilizations and even World War III. 

In recent months, the former Speaker of the U.S. House of Representatives, Newt Gingrich, has expressed frustration that terrorist leader Osama bin Laden is still at large, that Afghanistan is still insecure and that Iraq is still violent. Furthermore, he notes that North Korea and Iran are still building nuclear weapons and missiles.

Gingrich called on the U.S. Congress to pass a law declaring that the country is engaged in what could be World War III. Such a law, in his opinion, would enable the United States to use all its resources to defeat the enemy.

Gingrich's remarks have elicited mixed reactions. Michael Ledeen, a scholar at the American Enterprise Institute and author of the book, The War Against the Terror Masters, defines the current campaign against global terrorism as World War IV.

"I call it [World War] Four because we had the two hot world wars and than we had the Cold War, which was also a world war. So that would be World War III for me. And this is the fourth [world war] because our Western civilization is under attack from violent jihadists all over the world: from South America to Asia, Indonesia and, of course, Western Europe and the Middle East, and the United States. So you can't get much more global than that," says Ledeen.

Terror War or World War?

Some historians agree. Dennis Showalter, at Colorado College in Denver, says current ideological and armed conflict, as well as terrorist attacks wordwide, constitute a major global crisis equivalent to a world war.

"One never wishes to overuse this world-war trope, but certainly we are dealing with a comprehensive crisis with a global dimension," says Showalter. "Its scope far exceeds the Israeli-Palestinian issue, the question of Muslim acculturation in  Europe. I think it's comprehensive and I think it's something that has deep historical roots."

Professor Showalter says that the global war on terror has more characteristics of a world war than the first two world wars, which he likens to civil wars. "Both World War I and World War II were essentially civil wars within Western civilization -- World War I, obviously. I mean, this was a case of states in societies with a very broad spectrum of common values, tearing each other apart."

Professor Showalter says one important characteristic of a world war is that it has an ideological dimension. He notes, for example, that the Nazis, the Communists, and others all fought for their worldviews. In that respect, he says World War II was more of a global conflict than World War I.

"And I would say that the key to a true world war is global, universal involvement. And that involves communications technology. It involves transport technology and it involves what our French friends call 'mentalite'. And I think in that context, this thing we are in now is at least as much of a global war as World War II," says Showalter.

But some scholars disagree. Alex Roland, a professor of military history at Duke University in North Carolina, says the two world wars were exceptional events, peculiar to the first half of the 20th century. One of their unique characteristics was the ability to determine the future of nations.

"Nazi Germany and imperial Japan - - that is, Japan under the absolute control of the emperor - - their future was at stake and they both disappeared in the same way, for example, that in World War I, [Ottoman] Turkey disappeared. So the fate of nations was at stake. It's not at stake now in the so-called ´war on terrorism´," says Roland. "This is just the most recent in a whole series of terroristic campaigns that have been made against advanced industrialized states in the 19th and 20th centuries, and it is not to dismiss them as unimportant. Each one has been significant in its own way, but they don't come any place near being world war."

Professor Roland says another characteristic of world wars is the unprecedented number of casualties - - tens of millions of people. The Cold War, he says, was actually waged to prevent another world war. "And the Cold War never resulted in a direct major exchange of weapons between the United States and the Soviet Union, but rather a whole series of proxy wars among their satellite states. But even those wars didn't add up to anything like the scale of the world wars."

War as a Metaphor

Professor Roland says a world conflict of that scale is not likely to happen in the foreseeable future. He notes that Americans often use the word war as a way to emphasize the gravity of an issue.

"We've had a war on cancer. We've had a war on poverty. It was part of the rhetoric of the United States in the 20th century to declare war on things. Franklin Roosevelt back in the depression, even before World War II, declared war on the depression and used explicitly military combatant language to indicate the height of the priority that he was giving to this as a national issue. And that's what we've been doing ever since. But it's all rhetoric," says Roland.

American scholars and political analysts are not united on how to define the current global conflict, but all agree that terrorism is a serious threat to humanity and every effort must be made to defeat it.

This story was first broadcast on the English news program,VOA News Now. For other Focus reports click here.