I have written previously about discrimination, racism, and the African American experience in the Vietnam War. In this answer, I focus on the Green Berets, but much of it is applicable on the structural racism that was present in the United States Armed Forces in the Vietnam War era. This answer looks at it from the other side and talks about the treatment of African American POW:s by their North Vietnamese captors.

I will therefore look closely at the Asian American experience. Before we start, I feel like it is important to add a disclaimer: The scholarship within the field of American minorities (that are not African Americans) in the Vietnam War is not extensive and it is a burgeoning field. There are thousands of stories to be uncovered and if you know a Vietnam War veteran who belongs to a minority group, please consider interviewing them or in other forms recording their experiences during the war. You can donate your findings to the Veterans History Project that is hosted by the Library of Congress.

With this said, and with the lack of source material to further contextualize the racism that Asian Americans endured during the war, I will focus on personal/individual racism. Larger questions about structural racism and how this impacted Asian Americans in the United States Armed Forces requires additional research (and would make for a great potential thesis subject for any of you grad students out there!). The majority of the examples drawn in this answer will be from Japanese Americans (as compiled by Toshio Whelchel in From Pearl Harbor to Saigon: Japanese American Soldiers and the Vietnam War).

As Whelchel has identified, one of the most reoccurring themes for Japanese Americans going through basic training was something called the "gook syndrome". This was the continuous use of the derogatory and racist word "gook" to harass and bully Japanese (and likely other Asian) American recruits. This should be understood within the context of the categorization of the enemy in racial terms, something which was continuously presented to the American soldier. Their enemy in this war was meant to be unmistakably Asian. Asian American recruits were therefore easily targeted and turned into 'the Other', as being something alien. For Japanese Americans, the repeated use of the racial slur "Jap" added additional humiliation. Raymond Imayama, who served in the United States Marine Corps, vividly describes the form racism during basic training could look like for an Asian American:

We [Raymond and his friend] really stood out, being the only Asians in the platoon. Near the end of boot camp, since we were fighting the war in Vietnam, the DI said to our platoon, "You want to see what the enemy looks like?" The DI put me and my friend in front of the platoon and said, "This is what the Viet Cong looks like, with slanted eyes. This is what a gook looks like, and they all dress in black." That was really hard to take. I felt like I wasn't an American. In boot camp the DIs referred to me as a gook and a Jap. When I was in Vietnam, I slugged a Marine sergeant for calling me a gook. During basic training, I was harassed by a couple of recruits who called me a gook, but I told them that I was born here.

In fact, several veterans whose accounts were published in Whelchel's book had actually been born in internment camps during the Second World War.

Racism didn't stop at the end of basic training. Throughout their tours in South Vietnam, Japanese Americans were the target of racism. The racial slurs that they had encountered in boot camp would follow them and sometimes take different forms. Soldiers would be mistaken for being Vietnamese, and were frequently challenged on it. For example, American military police would question Japanese American soldiers for wearing American uniforms. "I would be dressed just like other Marines on the jeep, and I would always be asked if I was Vietnamese," Robert Yoshikawa explains, or as Marcus Miyatomo put it,

Part of this dehumanization [of the Vietnamese] was the paranoia about who the enemy really was. I think that many Marines lost the ability to make that distinction, and that realization started to bother me because I was Asian. If I could be mistaken for a Vietnamese, then I could be a gook; in the eyes of many Americans, I was already a gook! That really came home with me, that uneasy feeling, that sense that something was wrong, that there was a distortion.

Richard Chan, a Chinese American soldier, also encountered the frequent frustration of being mistaken for being Vietnamese. From Johnnie Clark's memoir, Guns Up!: A Firsthand Account of the Vietnam:

“It just hit me the wrong way. Sometimes I get fed up with explaining my nationality. I'm a good eight inches taller than your average Vietnamese, and they still assume that I'm one of them. You know that corporal that you think so highly of?” he said sarcastically.

“Corporal James? The stocky little jerk that acts like a general?"

"Yes. Him. He told me he didn't trust Kit Carson Scouts [former PLAF/PAVN soldiers], and for me to watch it."

"You're kidding! What did you say?”

“I told him I didn't particularly trust Vietnamese scouts either, or corporals who weren't aware of new replacements. That seemed to stump him. He walked with this ignorant look on his face.”

Not all Asian American soldiers experienced racism, however. Some, like Larry Matsumoto who was an Army Ranger, explained that "I was never called a gook during my tour of Vietnam". Others faced racial slurs being thrown at them from soldiers from allied nations, as Robert Yoshikawa experienced when he was called a "Number ten fucking Jap" by a South Korean Marine. However, even if you weren't the target of racism while wearing a uniform, you were still very conscious about racism towards Asian that surrounded you. Melvin Wadachi explains,

As far as being Asian, I think the hardest part of the war was not so much any particular incident or experience but the knowledge of a latent racist activity going all around me on a day-by-day basis. Everytime I saw some drunk GI kick a Vietnamese girl, it reminded me that the GI was kicking her because she was Asian, a gook; if she were white, the GI would not be doing that.. If Vietnam were Germany, this overt racism would not have happened.

In conclusion, Asian Americans experienced personal/individual racism on a recurring basis. The liberal use of racial slurs by American soldiers was closely tied to the dehumanization of their Vietnamese enemy which was an integral part of basic training. Like Marcus Miyatomo so succinctly described it, the distortion and the blurred lines between the enemy and the Asian American on basis of race meant that Asian Americans felt alienated. When Don Mitsuo was dressed up as a PLAF soldier and placed in front of his platoon, it was not something that white or black soldiers would have gotten to experience. When his drill instructor said, "This is what your enemy looks like. I want you to kill it before it kills you," Mitsuo became part of that dehumanization -- both of the enemy and of himself.

I can't speak to the experience of African American soldiers, but I can comment on some Asian American experiences during the war. You are correct in your hypothesis that racism directed against Asian American soldiers was prevalent. The contradiction of "looking like the enemy" was especially resonant for Asian American soldiers, and resulted in many altercations between Asian Americans and U.S. military officers.

For context, the Vietnam War coincided with the Asian American Movement, a period of heightened Asian American nationalism (in fact, the term "Asian American" was coined by Movement leader Yuji Ichioka in 1968), so many of the sources I've picked up on are from interviews with activists and other political leaders in the Asian American community. [1]

An interview with Sam Choy, an Asian American who enlisted in June 1967 at the age of 17, describes the racism he experienced from within the military [2]:

I Wor Kuen: Were you the only Asian in the unit? [3]

Sam: Yes.

IWK: What kind of treatment did you receive?

Sam: Well, a couple of days after, the Viet Cong started shelling us. Then the other G.I.s started making comments about me looking like Viet Cong...It went on and got worse. They asked me what i was doing on their side.

IWK: When was this harassment the worst?

Sam: Right after the G.I.s got back from patrol...They started asking me where I was born, if I was a Communist...They thought I could turn traitor anytime.

Sam continued to experience racist harassment until he reached a breaking point. Recounting an incident with one of his sergeants:

Sam: He kept yelling all kinds of remarks like — "slant-eyed Chinaman, gook, chink" — and he went on and on. I just got madder...I went to get my rifle. I waited for them to come back and when they did, they started to sweet talk me to give my rifle up...I fired a warning shot and they froze.

By this time I was near the perimeter of the base and was thinking of joining the Viet Cong; at lest [sic] they would trust me.

Sam was caught, court-martialed, and sentenced to 18 months of hard labor at Fort Levenworth.

Gidra [4], an Asian American-produced magazine from UCLA, provided political coverage and articles about the experience of Asian American soldiers as well. The cover of Gidra's May 1972 issue (http://ddr.densho.org/ddr-densho-297-37/) depicts an officer standing over an Asian American G.I., facing down a (presumably) Viet Cong fighter:

Asian American G.I.: What should I do, Joe?

Joe (officer): Kill that gook you gook!

The June/July 1970 issue of Gidra also has an exposé on anti-Vietnamese racism within the military during the war covering a plethora of egregious acts of violence against Vietnamese civilians perpetrated by U.S. forces, from indiscriminate murder, based on the idea that "For some GIs in Vietnam, there are no Vietnamese people. To them the land is not populated by people, but by 'Gooks,' considered inferior, unhuman animals."[5] Thus, the war in Vietnam was infused with a racial angle that disproportionately impacted Asian Americans.

Mike Nakayama also recounted:

In classes, instructors called me 'gook' and and had me stand so other recruits could see what the enemy looked like. They would emphasize the ridiculous idea that the Vietnamese have no regard for human life and because they are "uncivilized" and Communist, we must kill them to protect them and democracy. [6]

There was also a sexist angle to anti-Asian animosity Asian American GIs faced. Nakayama continued, "The women were clearly regarded as sexual objects for the pleasure of men...Stories of slanted vaginas, weird sexual practices, and submissiveness were maintained by many G.I.'s who had never seen an Asian before and now believed us to be less than human." [7] Furthermore, not only was rampant sexualization of Asian women (esp. in Vietnam) prevalent, but also an Asian American soldier recounted this interaction with an officer:

Soldier: I had some pictures of these Asian girls I went to high school with. He [the officer] made some derogatory comments like, 'This looks like this whore I knew back over there (Japan)'...That's when he saw the picture of my sister...he started rapping about when he was overseas in Japan, and how he had this prostitute...Then he said, "What was your sister's name?" He knew I had an older sister, and he had seen the picture of her, and I guess he flashed back on his experiences...And I'd tell him and he asked, did he have a Japanese name, so I'd tell him her Japanese name, and he'd say, 'Yeah, that's her. That's the prostitute I had.'"[8]

Evelyn Yoshimura, who wrote the article featuring the preceding anecdote, extended the dehumanization of Asians explicitly to its impact on Asian/Asian American women, noting that "The view that Asian women are less than human helps perpetrate another myth — that of the White woman 'back home' being placed on a pedestal." [9] Recounting another Asian American soldier's story:

I wanted to get married when I was in Vietnam [to a Vietnamese woman], but they (the Military) wouldn't let me...I went to my Section Chief, and he said, 'Man, you don't want to marry one of these 'gooks' over here. They're not civilized...Man, they'd say stuff like, 'She's not an American...You think you want to marry her now, but that's because there are no round-eyed [Caucasian] chicks around. They said that to me, you know, I'm an Asian too, but they said that to me. [10]

These are just a slice of stories from Gidra about Asian American personal experiences as Vietnam War soldiers that I've encountered. While it's difficult to generalize from these personal experiences to a collective statement on the "Asian American experience" as Vietnam War soldiers, these incidents and their presence in major Asian American sources (i.e. Gidra) of the time show their salience within the Asian American community. Hope this partially answers your question, and if you have any more questions about Asian American history/studies, I'm happy to point you to some sources — it's my area of (undergrad) study.

[1] See Karen Ishizuka, Serve the People (London: Verson, 2016), especially Ch. 3.

[2] Reprinted in Ryan Yokota, "Interview with Pat Sumi" in Asian Americans: The Movement and the Moment, eds. Glenn Omatsu and Steve Louie (Los Angeles: UCLA Asian American Studies Center Press, 2001), 16-31.

[3] I Wor Kuen (IWK) was a leftist Asian American political organization associated with the Asian American Movement. Their name comes from the "Righteous and Harmonious Fists" of the Boxer Rebellion. They conducted the interview.

[4] The entire Gidra archive is available to view on Densho at http://ddr.densho.org/ddr-densho-297/.

[5] Norman Nakamura, "The Nature of G.I. Racism," Gidra 2, no. 6 (1970): 4*.*

[6] Mike Nakamura, "Nam and U.S.M.C." Gidra 3, no. 5 (1971): 17.

[7] Ibid.

[8] Evelyn Yoshimura, "G.I.'s and Asian Women," Gidra 3, no. 1 (1971): 15.

[9] Ibid.

[10] Ibid.