The effects of French colonialism in Indochina was to change the relations between Laos, Cambodia and Vietnam. The hierarchical system between these countries, with Vietnam at the top, was taken advantage of by the French to gain control of Indochina. By maintaining the Vietnamese at the top of the hierarchy in the region (through providing education in Vietnam, better transportation and communication for the Vietnamese) the French gained control over the territory. As I understand it, the territory was pretty stable until the introduction of communistic political ideas from the North through China.

With the introduction of communism, all of Indochina was split over which route of independence to take: an independent, unified Indochina, or each state independent from each other and the French. This caused a lot of internal conflict within Indochina. Also, strong communistic Vietnamese forces in Laos and Cambodia caused problems for these countries.

Vietnam fought for independence, against the French, and acted as if fighting for the entire region's independence to smooth over relations with neighboring countries (Laos and Cambodia). This was because they share the same borders and the Vietnamese wished to prevent attacks from within Indochina because that would severely weaken or destroy they're crusade against the French.

I believe the text implied that if the French had colonized Indochina in a manner similar to Dutch colonization of Indonesia, that the theoretical evolution of Indochina would have been a unified Indochina instead of three independent states.

I personally believe that colonization of Indochina could not have occurred in a manner similar to Indonesia because the Vietnamese would have resented being treated equally with the Lao and Khmeres. Equal treatment would have made it difficult for the French to have strong support in the region and colonization impossible. It was favoritism that enabled the French to colonize Indochina.