请高手们帮忙看看这一句话怎么理解，大全里第二篇的第二段第一句

“Reform” in America has been sterile because it can imagine no change except through the extension of this metaphor of a race, wider inclusion of competitors, “a piece of the action,” as it were, for the disenfranchised.

这个是阅读大全里第二篇的第二段第一句。后面的几个重句跟前面怎么连起来的，是什么关系，谢谢！

这句在杨鹏难句里出现了.

解释是这样的:在美国的所谓的改革是无效的,因为这种改革改革不能构想出任何变化,除了通过扩展这个比喻中的竞赛的范围,除了通过更广泛得包括竞争者,通过给这些没有发言权的人提供一个类似于"参加进来的机会".

“Reform” in America has been sterile because it can imagine no change except through the extension of this metaphor of a race, wider inclusion of competitors, “a piece of the action,” as it were, for the disenfranchised.

简化一下：我觉得是这样:

“Reform” in America has been sterile because it can imagine no change except through the extension of this metaphor of a race,
        wider inclusion of competitors, “a piece of the action,” as it were,
        for the disenfranchised.

红色的是插入结构，可以扔掉。

划线部分 是 主干----后面 接两个 补充 内容的同位语。