For 40 years, Arab and Muslim heads of state, their handpicked ambassadors and their state-run media outlets repeated time and again that tensions in the Middle East would abate if only one thing happened: Israel withdrew from the occupied territories, and reverted to the borders that circumscribed the Jewish state prior the Six-Day War of 1967.

So prevalent in the regional discourse did this strain of thinking become that even Usama bin Laden, the Saudi-born leader of a terrorist network headquartered in Afghanistan and Pakistan, eventually adopted it as one of the pretexts for al Qaeda's attacks on civilians, which reached their bloody climax on Sept. 11.

But the wave of street protests and government collapses spreading through the Arab world over the last month belies this notion. The grievances voiced by the demonstrators, and the responses from besieged Arab governments, have not touched on the Israeli-Palestinian conflict at all; rather, the underlying friction has centered on the repressiveness of Arab and Muslim governments against their own citizens and the accompanying lack of economic opportunities.

Compounding the problem for Mideast despots -- both those directly affected by the current wave of protests, and those eyeing it nervously from within their gilded palaces -- are the raw numbers, the demographics, underlying the phenomenon. The tyrants' antagonists are not conventional armies or coup plotters but literate and disaffected young people, more of them than ever before, armed with access to instant, global communications in the form of social networking media like Twitter, Facebook, MySpace, and the Internet.

Of 12 selected Arab-Muslim states in the Middle East, six of them -- Egypt, Jordan, Morrocco, Oman, Saudi Arabia, and Yemen -- house populations where more than 50 percent of the citizenry are under the age of 25. For the other six -- Bahrain, Kuwait, Lebanon, Qatar, Tunisia, and the United Arab Emirates --  the "under 25s" make up between 35 to 47 percent of the population.

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In Yemen, site of major protests last month, and a state where the ruler of three decades' standing has preemptively announced he will not seek to extend his reign, some 75 percent of the population is under 30, and the poverty rate exceeds 45 percent. In Egypt, site of the most awesome spectacle of youth revolt since in decades, some 66 percent of the population is under 30, while fully half the country's 80 million citizens lives on less than $2 per day.

As the American saying goes: You do the math.

The Mideast is now home to more than 100 million people between the ages of 15 and 29, the largest youth cohort in the region's history. This fact, and the precedents set in Tunisia and Egypt suggest strongly to demographers and sociologists that other Arab-Muslim societies could face similar uprisings.

"Since 1980, the Arab world has experienced the highest rate of [population] growth of any region in the world," notes Kenneth Pollack, director of the Saban Center for Middle East Policy at the Brookings Institution in Washington. "It has grown at a blistering 2.7 to 3.2 percent per year. That is a phenomenal rate of growth and what it has meant was lots and lots of young Arabs entering the job market. But the problem is that the Arab economies have been sputtering during the same period of time, creating far too few jobs."

Egypt, for example, has needed to create 750,000 jobs a year to keep pace with population growth and the relentless appearance of new entrants into the labor pool; but under the Mubarak regime, Egypt has barely seen half that amount in most years, and unemployment has grown accordingly. In his 2008 book, "A Path Out of the Desert: A Grand Strategy for America in the Middle East," Pollack argued that these mathematical realities would leave Arab despots susceptible to a youth revolt.

"What you see across the Arab world is a population that's deeply unhappy with its economic circumstances, because of the widespread unemployment, underemployment, the low wages, the massive disparities between rich and poor all across the region," Pollack told Fox News. "But this has been badly compounded by autocratic governments. ... And that frustration builds over time, and created a pre-revolutionary situation that has existed in all the Arab world for at least the last decade. ... This is exactly the kind of thing that can spread, because the kindling is all there, and all it took is for someone to strike a match."

Other analysts, however, cautioned that the differences between Arab societies, and their regimes' relative wealth, can play a decisive role in determining where a youth uprising will succeed. Those regimes endowed with huge reservoirs of cash, principally from oil revenues, will be better able to withstand the onslaught of Twitter warriors, goes this line of thinking.

"In Iran, they use the dividends of petrodollars to feed an entire class -- the Revolutionary Guard (Corps)," said Walid Phares, author of "The Coming Revolution: Struggle for Freedom in the Middle East" and a Fox News contributor. "This sustains three to four million people who will keep the regime alive when it comes under attack. ... (Recently deposed Tunisian President Zine al-Abidine) Ben-Ali had no economy and no cash, so no one defended him. The army was poor, so they didn't defend him."

Middle East analysts are watching keenly to see if the fervor in Tunisia, Egypt, Jordan and Yemen will spread to Saudi Arabia, the birthplace of Islam and home to its two holiest sites. It also holds more than 20 percent of the world's proven oil reserves.

"Saudi Arabia is ultimately the key," said Pollack. "King Abdullah recognized this problem (of under-employed youth) five or six years ago and embarked on a comprehensive, if gradual, program of reform. The big thing to watch in Saudi Arabia is the king's health. He is over 80; he is not in great shape. If he dies before his reforms can become institutionalized, you could see very big problems in Saudi Arabia."

James Rosen joined Fox News Channel (FNC) in 1999. He currently serves as the chief Washington correspondent and hosts the online show "The Foxhole." His latest book is "A Torch Kept Lit: Great Lives of the Twentieth Century" (Crown Forum, October 4, 2016).