The attitudes of of Native Americans towards the federal government changed rather drastically during the war, particularly after the attack on Pearl Harbor. In the pre-war years, tribal governments were quite resistant to interference by the Bureau of Indian Affairs (BIA). In 1933 the BIA had enacted what is often called the "Indian New Deal", an act that imposed federal restrictions on Navajo farming and governance, further solidifying the fundamental distrust in the relationship that had been creating during the Indian wars.^1 The attempts by BIA Commissioner John Collier to assimilate Native Americans into mainstream society only further served to aggravate tribal aggression.^2

As the world descended into WWII and US nationalism became more exaggerated, the resentment towards the nation itself shifted. By 1940, the Navajo Tribal Council made a declaration of solidarity with the US in war, saying

There exists no purer concentration of Americanism than among the First Americans.^3

That is not to say that the sense of Nationalism was universal by this period. In 1940, one Choctaw chief was recorded as saying

Choctaw Indians never vote or pay poll tax. The white friend here say we are not allowed to vote… If we are not citizens, will it be right for Choctaws to go to war?^4,5

In order to assuage these debates and encourage registration, the BIA established 125 registration centers for the Navajo and extended the registration period to 3 days. With the Sioux, they went as far as hiring translators to explain the draft laws in Lakota. But none of these were enough to completely quiet discontent among the tribes.

Pearl Harbor quelled this debate almost immediately. Native American nationalism surged after the attack and by 1943 the BIA reported a registration rate of over 99%. It would be a mistake to completely attribute this solely to nationalism though. There were many concurrent factors, including hope of better conditions outside the reservations. To quote code talker Carl Gorman:

It sounded like the worst that could happen was I'd have a roof over my head and be eating regular.^7

The Navajo relationship with the Federal government is complex. Before, during and after the war, there was significant discrimination towards natives. But if you were a young man entering after Pearl Harbor, you most likely would have been very nationalistic and willing to voluntarily enlist.

If you'd like to know more, reference 5 is one of the most comprehensive books around on the subject of American Indian attitudes and involvement with WWII.

EDIT: Corrected formatting and page error in ^4

^1 Grinde, Donald. Navajo Opposition to the Indian New Deal Equity & Excellence in Education Vol. 19, Iss. 3-6, 1981

^2 David Wallace Adams, Education for Extinction: American Indians and the Boarding School Experience University of Kansas Press, 1995, pg. 58

^3 Iverson, Peter, and Monty Roessel. Diné: A History of the Navajos. Albuquerque: University of New Mexico, 2002, pg. 48

^4 Riseman, Jed. "'Regardless of History'? Re-Assessing the Navajo." Australasian Journal of American Studies, 2007, pg. 49

^5 Bernstein, Alison. American Indians and World War II: Toward a New Era in Indian Affairs University of Oklahoma Press, 1991

^6 Riseman, pg. 51

^7 Riseman, pg. 57