“Traditionally, civil wars are fought between the state and some sorts of rebel groups that are hoping for either autonomy or to capture the state. Now, we see more complicated civil wars in which there are economic groups hoping to use the chaos to make profits and a lot of international involvement from external states so that there’s really a blurred line between civil and international war”.
(Sarah Kenyon Lischer, Wake Forest University)
American involvement in the Vietnam war was so overarching and profound that it is totally legit to use the term “resistance war against America'' to address this war in international discourses. It’s Washington who actually stood behind the 1963 coup and the execution of the Ngô brothers, although apparently the opposition groups held accountable for it. Diệm was overthrown because he wanted to make South Vietnam independent of America. Madame Nhu, in her memoir Le caillou blanc, also shares this view. Her controversial remark on Thích Quảng Đức’s death has always been taken out of context; what she indeed said was that such a political act was not “self-sufficient” because they had to use “imported gasoline”.
Reading the literary weekly Văn (1957-1958), the first newspaper by the Vietnamese Writers' Association (Hội Nhà văn Việt Nam), we could see how ‘democracy’ was abused as a front to denounce Diệm, and such practice was also found in the South’s media, backed by the opposition groups such as the Caravelle Manifesto group. This pretty much reminds me of how today’s RFA depicts the current regime. Maybe not until we allow ourselves to believe that Diệm was also some kind of patriot with a different political vision and authoritarian policies will we wake up to the intricate historical truth.
Back in the days after the 1954 Geneva Conference, it’s the First Republic that offered a home for the emigrants from the North, including the anti-communist politicians and intellectuals, namely Vũ Hồng Khanh, Nguyễn Tường Tam, Trần Trọng Kim, Vũ Đình Chí, Phùng Tất Đắc, Trần Tuấn Khải, Vi Huyền Đắc, Đinh Hùng, Vũ Hoàng Chương, Tạ Tỵ, Nguyễn Gia Trí, Nguyễn Vỹ, Lê Văn Văng, Lê Văn Trương, Mai Thảo, Vũ Khắc Khoan, Nghiêm Xuân Hồng, Mặc Đỗ, Thanh Tâm Tuyền, Dương Nghiễm Mậu, Doãn Quốc Sỹ, Võ Phiến, Nguyễn Mạnh Côn, Nguyễn Sỹ Tế, Trần Thanh Hiệp, Duyên Anh, Phạm Duy, Phạm Đình Chương, Cung Tiến, Thái Thanh, and so on. The victims of the land reform, the Catholic groups in Bùi Chu - Phát Diệm, the religious sects Cao Đài and Hoà Hảo, the political parties Đại Việt and Việt Quốc also found their place here in the South. However, we must admit that the South Vietnam government gradually became corrupted, especially from 1963 onward, and that the legitimacy of the aforementioned political forces is questionable since they did not directly fight against the French in the battle of Điện Biên Phủ. And, to be fair, Diệm’s government was pretty much in the same situation as that of Trần Trọng Kim cabinet since they relied solely on the foreign power. Diệm’s death in 1963, and the fall of Saigon soon after the U.S. abandoning South Vietnam in 1973 proved that such a government is undeniably a puppet government.
'hey, long time no see, how you doing'
So to say that the 1954-75 war is a civil war is to diminish the American involvement and thus mislead people into thinking that such a war has nothing to do with the U.S, which is far from the truth. On the other hand, to say that it is not a civil war is to devalue the will and political stance of many anti-communist nationalists in the South. 
Likewise, to say that the 30 April 1975 was a happy ending is to neglect the suffering of those boat people and prisoners in post-war re-education camps who, after all, are still our compatriots, whereas to say that it was a disgrace is to offend those who had sacrificed for the reunification and independence day for over 20 years.
What we would rather do in the middle of such a dilemma is to stop oversimplifying the complexity of history (“history is just a continuation of events pointing at different directions”, Tạ Chí Đại Trường), and stop regarding our brothers and sisters as alienated or “other species”. If there’s something such a nation’s fate is to teach us, that must be compassion and solidarity. And that’s what the Resolution No.36 (2004) is about. 
Xin lấy máu làm dầu soi sáng, 
Cho con cháu mình soi tỏ mặt nhau. 
Nguyễn Cao Kỳ said the historical mission of his generation was to reunite the country territorially, and the North made it, maybe it’s our generation’s mission to reconcile and reunite our people spiritually, which might take a long way to go, unless Dưa Leo and Duy Nguyễn get married. 
Just kidding.