Its the third verse of the "Defence of Fort McHenry", written in 1814 during the War of 1812. A little later, it got a title change to "The Star Spangled Banner" after it had been set to (interestingly enough, 50 year old British) music and then and a little expos-facto, was made the national anthem in 1931.
"Heaven" and "the Power" clearly wanted the United States to exist, just the way it is. It was born and lived its run-up to anthemhood in the days of "Manifest Destiny". You could call this a real boom that swept the nation - and for right reason. That American were bound to take over all of the continent/west and make it just like Europe was - to restore civility to the wild west.
I wonder if God had called us to greater things, if we would have heard him over our own hubris?