英语语法高手：more perfect用法

有More perfect 这样的用法。如在美国宪法的序言中：We the people of the United States,in order to form【a more perfect Union,】establish justice,insure domestic tranquility,provide for the common defense,promote the general welfare,and secure the blessings of liberity to ourselves and our posterity,do ordain and establish this Constitution for the United States of America。我们合众国人民,为建立更完善的联邦,树立正义,保障国内安宁,提供共同防务,促进公共福利,并使我们自己和后代得享自由的幸福,特为美利坚合众国制定本宪法。