※ 引述《ComeTureLou (千层酥的千晨)》之铭言：
: 其实这两个国家形状真的满像的
: 可是差别就是我不懂
: 美国州跟州甚至还有一些法律不一样
: 人家也不会吵独立 也不会怕有哪一州要独立
: 民主国家都能做到这样了
: 那中国为什么会怕呢?
: 人家美帝都可以做到不会吵独立了
: 难道天朝有做不到的事情?
美国一些有钱的州，里面也有人吵独立了喔
其中，可以自行看下面这个案例
简单白话来说，就是:
"除非透过革命或获得联邦政府同意，否则你不能自联邦政府中独立出去"
Texas v. White
https://en.wikipedia.org/wiki/Texas_v._White
In accepting original jurisdiction, the court ruled that, legally speaking,
Texas had remained a United States state ever since it first joined the
Union, despite its joining the Confederate States of America and its being
under military rule at the time of the decision in the case. In deciding the
merits of the bond issue, the court further held that the Constitution did
not permit states to unilaterally secede from the United States, and that the
ordinances of secession, and all the acts of the legislatures within seceding
states intended to give effect to such ordinances, were "absolutely null".