Though scantly reported, this is potentially the most important geopolitical development in the Middle East since the signing of the Balfour Declaration in 1917, which promised a homeland for the Jews and, incidentally, also created the Saudi state - with full British blessing - in 1932.
Abu Bakr Al-Baghdadi, the elusive leader of the Islamic State and self-proclaimed new caliph, referred to the Balfour Declaration in his diatribe.
However grudgingly, one cannot but admire his political acumen, understanding as he does that the road to Jerusalem leads through Mecca.
For if there is another Middle Eastern country ripe for bloody, internal strife, it is the Wahhabi Kingdom.
Led by a notoriously repressive, corrupt and hypocritical royal family, considered apostates by pious Muslims and despised by large sections of its largely impoverished population, it is riven not only by political back-stabbing but also, more crucially, intractable tribal, regional and sectarian divisions.
Consider, given most recent events, Al-Jouf, the northern-most province bordering Iraq, where locals have strong historic tribal ties with Iraqis.
In 2004, Al-Jouf witnessed an extraordinary rebellion against the ruling Al-Sauds, partly in support of the Palestinians and led by Saudi jihadis who had returned from Afghanistan.
The region's deputy governor, the city's top Islamist judge, and its chief of police were all executed in the space of a few weeks, amidst mass public demonstrations and the country's worst prison riot. The local tribes, hell-bent on revenge, would surely be eager to join the ranks of the Islamic State.
Terrifyingly, Saudi Arabia's main military garrison town, Tabuk, is a short drive from Al-Jouf, and is linked by a major highway to Jordan - a strategic gateway, in other words, to a final jihadi assault on Israel.
Such an outcome would precipitate uprisings elsewhere in Saudi Arabia, most obviously on the Saudi-Yemeni border - where, as in Al-Jouf, cross-border tribal allegiances trump national identity.
The largely porous, mountainous Saudi border region of Asir has long provided access to Saudi Arabia for suicidal jihadis from Al-Qaeda in the Arabian Peninsula - a Yemen-based outfit which, until the emergence of the Islamic State, was considered the biggest threat to regional stability.
Then there is the Eastern Province, home to most of Saudi Arabia's oil fields, where the majority of the local population are despised Shia, and where a low-level rebellion against the Al-Saud rule has been rumbling for three years. This is Iran's ultimate goal.
The scenario, then, is truly nightmarish - both for Israel and the global economy.
But one cannot but note the irony that, should Washington continue to dither, the outcome will be that Israel's two main enemies, the jihadis and Iran, may one day be celebrating their respective conquests - despite loathing each other with an equal passion.
