2018年2月，蔡美兒的第五本書出版。《政治部落：群體本能與國家命運》一書的主題是，對群體的忠誠往往超過[[意識形態]]的考慮。她探討了未能意識到這一點對美國外交政策的失敗和[[唐納德·特朗普]]在國內崛起的影響。這本書受到了來自各個[[政治派別]]的壓倒性好評。為《紐約時報》撰文的{{tsl|en|David Frum|大衛·弗魯姆}}稱讚蔡美兒願意接近“其他人通常會踮著腳尖走的禁區”。<ref name="nytimes">{{cite web |first=David |last=Frum |url=https://www.nytimes.com/2018/03/01/books/review/amy-chua-political-tribes.html |title=The Battle Over What It Means to Be American |publisher=[[The New York Times]] |accessdate=2020-03-13 |date=2018-03-01 |archive-date=2020-11-09 |archive-url=https://web.archive.org/web/20201109031420/https://www.nytimes.com/2018/03/01/books/review/amy-chua-political-tribes.html |dead-url=no }}</ref> 《[[華盛頓郵報]]》形容這本書“緊湊、有洞察力、令人不安，但最終還是充滿希望”，{{tsl|en|Ezra Klein|埃茲拉·克萊恩}}在他的Vox播客上稱這本書“引人入勝”。<ref name="washingtonpost">Jonathan Rauch, [https://www.washingtonpost.com/outlook/have-our-tribes-become-more-important-than-our-country/2018/02/16/2f8ef9b2-083a-11e8-b48c-b07fea957bd5_story.html "Have our tribes become more important than our country?"] {{Wayback|url=https://www.washingtonpost.com/outlook/have-our-tribes-become-more-important-than-our-country/2018/02/16/2f8ef9b2-083a-11e8-b48c-b07fea957bd5_story.html |date=20201125133724 }}, ''The Washington Post'', Retrieved 2018-03-30.</ref><ref>Ezra Klein, [https://www.vox.com/ezra-klein-show-podcast "The Ezra Klein Show"] , ''The Ezra Klein Show'', 2018-02-26.</ref> 這本書受到了一些批評。 《衛報》稱之為“一本立意好的書，但未自圓其說”。<ref>{{Cite newspaper|url=https://www.theguardian.com/books/2018/feb/25/political-tribes-amy-chua-review|title=Political Tribes review – an unreliable guide to the American Dream|last=Anthony|first=Andrew|date=2018-02-25|journal=The Guardian|language=en|access-date=2018-03-04|archive-date=2020-11-25|archive-url=https://web.archive.org/web/20201125133752/https://www.theguardian.com/books/2018/feb/25/political-tribes-amy-chua-review|dead-url=no}}</ref> 《金融時報》稱這是“一本重要的書”，並支持蔡美兒的論點，“美國的[[自由主義]]精英未能承認自己的{{tsl|en|Tribalism|部落主義}}意識，為特朗普的崛起作出了貢獻”；但它也指出，書中沒有回答如何創建一個“非部落世界”的“關鍵問題”。<ref name="ft">{{cite web|last=Tett|first=Gillian|date=2018-02-21|title=Us and them: how America divided into tribes|url=https://www.ft.com/content/f4e18952-157b-11e8-9e9c-25c814761640|work=Financial Times|accessdate=2018-03-04|archive-date=2020-11-25|archive-url=https://web.archive.org/web/20201125133753/https://www.ft.com/content/f4e18952-157b-11e8-9e9c-25c814761640|dead-url=no}}</ref>萬斯是蔡美兒的學生，也是《鄉間輓歌》的作者，他稱讚這本書，他說“政治部落是對傳統智慧的一種獨特的重要挑戰，寫得妙，可讀性很強。”<ref name="auto"/>