Books about "America's Christian heritage" usually tend to smooth over the difficult bits—Ben Franklin and Thomas Jefferson are re-cast as committed Christians, the Enlightenment is overlooked as an essential factor in the formation of the United States, and the sins of the people are marginalized in favor of hymns to religious nationalism.
Peter Marshall and David Manuel do a good job of avoiding the first two pitfalls, but while they don't ignore national or personal transgression in America's history, they do couch everything in terms of "God's plan for the United States." There's nothing wrong with believing God has a plan for the nations (it's right to believe that, in fact), but as their series progresses it becomes apparent Marshall and Manuel have something a little different in mind than simply asserting God's sovereignty.
This isn't a curriculum in any sense. The primary series consists of three books (The Light and the Glory, From Sea To Shining Sea, and Sounding Forth the Trumpet) for adults and older students; abridged versions of each volume are available for children (ages 9-12, or thereabouts) along with activity books (for ages 5-8) and study guides.
Both the adult books and those for kids are written in a narrative format that reads like a novel without dialogue. All the major events from the discoveries of Columbus to the end of the Civil War are included. The adult series is quite in-depth; the children's abridgements are more streamlined, and almost present a kind of bullet-point history lesson, though they're still readable and engaging.
The books for younger readers also spend more time on the providential aspects of United States history. A lot of this is open to interpretation (see the Our Thoughts section below), and parents will not want to simply have their kids read these books on their own. The reproducible activity books are to be used by kids not yet able to read the books; mostly just coloring books with limited text, there are a few crosswords and similar puzzles to complete.
The study guides are for parent/teacher use in presenting lessons based on each chapter of the student books. There are ideas for conversations, extra information, and games and activities. The questions for discussion could easily be modified to provide jumping-off places for written assignments or even reports. These are by no means necessary, but they are useful if you're using this series for school (though they do retain the authors' bias).
The Light and the Glory covers Columbus through the founding of the nation; From Sea to Shining Sea spans the infant United States to just before the Civil War; and Sounding Forth the Trumpet focuses on the Civil War. Those who favor a more Southern perspective should be aware that the authors pinpoint slavery as the issue of the Civil War; others will appreciate how they show the effects slavery had on the states' rights debate and economic concerns. Eli suggests a video, The Great Civil War Debate between Steve Wilkins and Peter Marshall, as a balancing point.
Throughout, readers are reminded that everything in America's history took place as part of God's unfolding plan for the nation. While God certainly has a plan for everything, and is sovereign over men and nations, they take things way too far, as this brief excerpt from The Light and the Glory for Children objectively demonstrates:
"The United States Constitution is one of the most astounding documents ever written by man. For two hundred years it has withstood the test of time. Why does it work so well? One reason is that it was divinely inspired." from The Light and the Glory for Children, page 156
Christians believe one document in the history of mankind was divinely inspired: God's Word, the Scripture, the Holy Bible of Jesus Christ. The Constitution is not part of the biblical canon, and is therefore not divinely inspired. End of story. This is the attitude demonstrated throughout these texts, however, and one which has led us to decide not to carry them.
In some ways, Marshall and Manuel do a good job of being honest. They don't discount the influence the Enlightenment had on our country's founding (though they also deny the extent of this influence), they don't try to Christianize people who were clearly outside God's covenant body, and they have no problem admitting that Americans have often turned away from God.
But they also do something rather shocking: time and again, they conflate God's covenant people with the citizens of the United States of America, and assert America's special place in God's program for human history, as a "city on a hill." When the Puritans used that phrase, it wasn't a national identity they were talking about, but their role as Christians. Some of America's ideals were doubtless rooted in those of the Pilgrims and Puritans who first settled the New World, but that doesn't mean what Marshall and Manuel evidently take it to mean, that all Americans are part of the covenant body.
To claim such a thing is outrageous. We are members of the covenant body of Christ through faith, and the acts of faith (baptism, the Lord's Supper, etc.). America has certainly been blessed with the presence of many godly men and women, and their ideas have to some extent shaped our nation, but we must never assume that God has blessed one country over another in the New Covenant: He has blessed His people, and they are called Christians, whether they're from Irian Jaya or Chicago.