Roberts' focus is the core Anglosphere; i.e., the UK, the USA, Canada, Australia, and New Zealand. During the 20th Century, the Anglosphere faced four great challenges. Three have been successfully seen off, with the Anglosphere triumphant: Prussian Militarism in World War I, Fascism in World War II, and Communism in the Cold War. The fourth assault arrived on 9/11 when the true menace of Islamic terrorism was finally brought home to the cultural and financial center of the modern Anglosphere.Source.
Indeed, just as Churchill's History was intended to rally the Anglosphere in the early days of the struggle against Communism, Roberts' intent self-evidently is to rally the Anglosphere against Islamofascism.
....If Roberts is right, whether the 21st Century extends the era of Anglosphere hegemony thus depends on whether the Anglosphere becomes a house divided against itself. The two great issues here are education and demographics. Most of the Anglosphere nations have seen a dramatic rise in Muslim immigration and population growth since the Second World War. This demographic reality has been coupled with the rise of multiculturalism as official state policy in much of the Anglosphere. Properly understood, the Anglosphere is not a collection of nations united by language and race, but rather a group of nations united by a common culture. Yet, in the name of multiculturalism, our political and educational systems have not pursued the goal of assimilation. To the contrary, throughout the Anglosphere, the notion that we should be inculcating the values of the Anglosphere among all our citizens of whatever race or religion has become anathema to the Politically Correct.
If political correctness allows the cultural threads of the Anglosphere to be torn apart, there is no hope for western civilisation and the western enlightenment. It will be lost history, a golden age looked back upon with an unutterably painful nostalgia. In its place will be bloody authoritarianism of whichever strain survives between the China-North Korea-Cuba-Venezuela-Bolivia axis, and the great Islamic Sharia Crusade. Shia and Sunni would need to temporarily put aside their differences in order to defeat the infidel authoritarians, but that could be done--as long as it was only temporary.
Eventually, after the blood of the infidels flows, the blood of the heretic--whether Shia or Sunni depends upon you point of view--must also flow to the glory of Allah.