As new Egyptian President Abdel Fattah al-Sisi prepares for his inauguration today, his most powerful Arab ally is deploying both threats and promises to ensure the Arab Spring cannot upset a new anti-Islamist front in the Middle East.

King Abdullah of Saudi Arabia last week urged Egyptians to embrace Sisi, the military man who drove Islamists from power in Cairo a year ago, and said they should to disown the “strange chaos” of the Arab uprisings.

It was Riyadh’s starkest message of support yet for Sisi, who won an election last month thanks to support from Egyptians hoping that a strong, military-backed government will bring an end to three years of political instability in the most populous Arab country.

Sisi’s win was undoubtedly a boost for Saudi Arabia, which had watched with horror as the Arab revolts toppled authoritarian leaders and brought President Mohamed Morsi of the Muslim Brotherhood to power in Egypt.

For Saudi Arabia, Sisi’s win sealed the end, for now, of the rise of the Brotherhood, the international standard-bearer of mainstream Sunni political Islam since it was founded in Egypt in 1928.

Since the movement has a following in every Arab and Muslim society, the example set by the Egyptian Brotherhood’s embrace of the ballot box poses a threat to the hereditary dynasties that hold sway in wealthy Gulf Arab states such as Saudi Arabia and the United Arab Emirates.

The movement enjoys substantial support from Islamist-friendly countries like Qatar and Turkey and its influence appears to have grown in countries such as Morocco, Tunisia and Libya since 2011.

The blunt, emotional language in the King’s message – which described troublemakers in the region as “the helpers of Satan and its troops on the ground” – laid bare an underlying power struggle in the region pitting conservative, anti-Islamist governments, represented by Saudi Arabia, the UAE and Egypt against countries such as Qatar and Turkey who appear to believe that Brotherhood represents the future of Arab politics.