帮助理解一句话,谢谢!Now, We believe we must bethe family of America,

帮助理解一句话,谢谢!
Now, We believe we must bethe family of America, recognizing that at the heart of the matter we are bound one to another, that the problems of a retired school teacher in Duluth are our problems. 这里的heart of the matter是问题的核心,后面为何不加is接we are bound one to another, that the problems of.,即使加了is意为我们联系在一起也不通顺啊?我们联系在一起解决问题是好事怎么能是问题的核心呢?
求解答,谢谢!