On Constructing the National Myth

I am familiar with the historical narratives of grand nations such as China and Spain. Both have easy themes to follow for the middle school history textbook writers, such as Spain's imperial conquest and China's recovery from Western powers' invasions. Does modern Spain try to downplay the Islamic part of their history Al-Andalus (711-1492)? It would not be difficult because Communist China successfully downplays other parts of its modern history deftly. The Tiananmen Square can still serve as symbolic, political space for modern China, because that is where Mao declared the establishment of the PRC. What happened on 1989 at the same location is just a wrinkle that can be overlooked, again and again. But not all countries have the convenience of 5000 years of culture and narrative capital. 
I have yet to read the textbooks of nations in decline, such as those of Cambodia's. I have written a historical sketch on the methods used for analyzing Pre-Angkor Cambodia in the book. In subsequent chapters, the author John Tully delves into the meat of colonialism, or I expected him to. I have heard many anti-colonial stories about the power of the colonizers, yet the French efforts seemed surprisingly clumsy. Tully shows that the French never really got their way in Cambodia for the sake of Vietnam to the extent that the British Empire meddled with Burma politics for the sake of India. Tully list an endless story of occupations and incursions of Vietnam, Siam, and eventually the French, three aggressors which are never independent of the others' influence. For example, one could argue that Vietnam saved Khmer culture by eliminating Muslim Cham domination and balancing Siam aggression 17th-18th century. Then Vietnam domestic insurgencies stalled all-out French domination of Cambodia in the 19th century.
Crafting and selling a Cambodian nationalism narrative would give anyone a headache. It is much easier for the state historian to white-wash the errors of the current dynasty/regime than to  make a coherent narrative from alternating foreign occupations and prolonged decentralization. Angkor Wat is one of the sites that struggles to fit into modern Cambodia's narrative. My friend and I had a brief disagreement about the lack of commercial billboards in the tourist region. She thought that the scenic area is perfect without billboards, while I thought that the Cambodian government could generate more revenue if they created more billboards surrounding Angkor Wat. Overall, I had the impression that the government could put more effort in preserving the area instead of relying on other countries' archaeological teams such as India, Japan, and China. Today, when reading The Short History of Cambodia, I realized that the Cambodian government may be purposefully sidelining Angkor Wat because the past-glory haunted modern Cambodia. Acknowledging the the Angkor Empire, then Southeast Asia's largest, would subsequently lead to the depressing downfalls and decline of Khmer culture. More research should be done before drawing conclusion between Cambodia's current state ideology and policy of neglect (given that there is one).
Yet perhaps Cambodia does not need an all-inclusive national myth. My college religious studies professor Oona Eisenstadt argued strongly against the Meta-narrative and influenced my view of history. The necessity for a neat conclusion from fairy tales to History erases the Other and possibly leads to violence. Christianity's Providence and Marxism's Revolution both erase the Other. Oona gave an intriguing speech on this matter by analyzing the Hunger Games with incisive opinions. German-Jewish thinker Walter Benjamin wrote about his ambivalence regarding revolution and a linear path towards "progress" in On the Concept of History. Subaltern historians similarly critiques nationalist narratives of India that oversimplifies. I have always sough to complicate the metanarrative: I pay attention to regional movements in China, such as the rising prominence of Uyghur identity and Shanghai identity, to name a few.
One friend challenged this critique on philosophical grounds: one essentialism (arguments for the particular) overtakes another essentialism (i.e. Orientalism or nationalism). He is not as optimistic of historiography as I am. I believe in the power of retelling the story from different perspectives and the impact it can have on future generations. Perhaps Cambodia can and has been exploring new ways of narrating the country's history without a linear one, which indicates doom and gloom since Angkor Wat.