It's also because the Saudis and their partners see U.S. power waning in the Middle East while Iran's is rising and because they believe the United States has made too many mistakes, particularly by invading Iraq.
If the GCC, currently consisting of Saudi Arabia, the United Arab Emirates, Kuwait, Oman, Qatar and Bahrain, does eventually extend into the Levant and North Africa, it could well deal a death blow to the 22-member Arab League.
The Arab League, founded March 22, 1945, in Cairo has failed in its primary mission of unifying the fractious Arab world.
The recent political turmoil, in which two Arab leaders have been toppled and three others are fighting for survival, has redefined the Arab world and pushed the normally cautious Saudis into a dramatically more assertive role as they confront Iran's plans for expansion.
The GCC, founded in 1981, was always a subset within the Arab League, which was dominated by Egypt.
But it was distinctive because all its members were oil-rich monarchies on the periphery of a region largely made up of republican dictatorships.
By inviting the relatively poor monarchies of Jordan, a Levantine state that has long sought an alliance with the Persian Gulf states, and Morocco, an Arab outpost on the Atlantic which has shown no particular interest in such a move, the gulf alliance seems to be aimed at splitting the Arab world in two.
The GCC states are worried they may not be immune to the political turmoil, which has already erupted in tiny Bahrain and nearby Yemen.
In March, the Saudis, in the name of the GCC, sent armored columns into Bahrain to support to the Sunni throne against what Riyadh saw as Iranian attempt to subvert the monarchy in an archipelago long claimed by Tehran.
This unprecedented action by the Saudis was a turning point that pushed them closer to a showdown with Iran and demonstrated Riyadh's determination to ensure stability in its neighborhood.
Egypt has long dominated the Arab League and the effort of the post-Mubarak interim government to restore Cairo's long-surrendered authority in the Arab world, including making up with nuclear wannabe Iran, caused unease in Riyadh and the gulf capitals.
"With the GCC trying to emerge onto the regional scene, it raises the question of what will happen to the Arab League, which, despite its dysfunctional status thus far, remains the main pan-Arab forum," observed the U.S. global security consultancy Stratfor.
"Egypt is … unlikely to accept life under the growing influence of the GCC states. In other words, we may see another intra-Arab fault line emerge."
The Arab upheaval has everything to do with the GCC move, as has Riyadh's belief that the United States is a waning power in the Middle East, a power that can no longer be relied on to support the gulf states and their oil.
A hard-hitting op-ed by Nawaf Obeid, a consummate Riyadh insider, published May 15 in The Washington Post detailed just how deeply the Saudi relationship with the United States has changed since it was forged by King Ibn Saud and President Franklin D. Roosevelt in February 1945.
"A tectonic shift has occurred in the U.S.-Saudi relationship," wrote Obeid, senior fellow at the King Faisal Center for Research and Islamic Studies.
"Despite significant pressure from the Obama administration to remain on the sidelines, Saudi leaders sent troops into Manama in March to defend Bahrain's monarchy and quell the unrest that has shaken the country since February.
"For more than 60 years, Saudi Arabia has been bound by an unwritten bargain: oil for security. Riyadh has often protested but ultimately acquiesced to what it saw as misguided U.S. policies.
"But American missteps in the region since Sept. 11, an ill-conceived response to the Arab protest movements and an unconscionable refusal to hold Israel accountable for its illegal settlement-building have brought this arrangement to an end.
"As the Saudis recalibrate the partnership, Riyadh intends to pursue a much more assertive foreign policy, at times conflicting with American interests."