The problem is that not everything about Manifest Destiny or American Exceptionalism is clearly unbiblical. Take for example the command of God to be “fruitful and multiply, fill the earth and subdue it.” What that meant in 1840 and what it means now is very different. In 1840, that scripture provided biblical backing to people longing to try their hand at “redeeming the earth.” Today, if that scripture is quoted at all, it is read apologetically and comes with an appeal for “Creation Care.” (I would argue that environmentalism is a major tenet of modern American civil religion.)
So, let me get this straight… the current thought that to leave our children straddled with imaginary debt incurred in large part because of wars cheered by Christians who believed they were ushering in the End Times is not civil religion, but protecting the environment is civil religion.
Be fruitful and multiply is not and has never been equal to manifest destiny. This is another example of “biblical values.” Manifest Destiny included the genocide of other peoples. The death of hundres of thousands. Taking lands not ours. There is nothing Christian about this.
Further, civil religion is part and parcel of American Christianity, on the both the left and the right. The blogger suggests that it is difficult to tell civil religion and Christianity apart. If that is the case, then I would challenge the blogger as to his Christianity.