“If you want peace, prepare for war.”
Ephesians 6:12-13 ESV
For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places.  Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand firm.
What shall I say of mankind but this, for any nation to enjoy any kind of peace and or security one must prepare for war. When God led Israel into the promised land he told them to purge it of all of the people living there for two purposes. First to establish them as a nation set apart from the rest of the world and second to keep them from adopting the gods and idols that were already there. Instead over and over they failed to expunge those who were not to dwell among them nor reject the ways they brought with them.
When Jesus came to bring salvation and established his church he gave commandments to live amongst the world. Instead of worldly security he gave us security within the kingdom of God. He did not call us to wage war as the world does yet he called us to take up arms against spiritual enemies. Against strongholds Satan held tightly. Strongholds within people, strongholds within governments on a more personal level within the officials who governed and not on the battlefield. Where believers failed was by not purging the ways the world taught us to live, and the ways it taught us to make war. At least on a spiritual level. Indeed as countries go there is obviously still a time for physical war, yet as Christians those must be fought within a fair and righteous way honorably toward believers and non believers alike with out partiality.
So brings me to America, which has long been known as a country, a nation that is Christian. In fact when you say it is a Christian nation that is in fact what you mean by compacting the previous sentence. Though the obvious looming precursor of Christianity itself is that you can not be born into the kingdom of God by the physical birth. You can not have faith by association. Indeed many are called to faith and salvation through belief in in the blood payment of Christ. Thus further a nation in itself can not be saved. There can be a hedge around a said nation for the glory of Christ eternal kingdom and the furthering of his glorious message of good news but eventually there would need to be a call to revival which there has been. The purpose of said nation would inherently not be a forever resting place for his followers nor a place to only reward obedience but perhaps a call to arms to protect his natural first earthly elect nation when the time came as it has and to further his call to his heavenly kingdom across the globe which it has. The reality though much to most of our heritage has been and continues to be stained by horrific acts done not only by the non believers but outstandingly by his church and in his name. In his revelation to John he did not seperate the chaff from the wheat when he talked to the churches therefore I will not either. I will say this, God calls both the church and non believers to repentance but holds each accountably different. Condemnation is not off the table.
Looking at the state of the union, I would be very weary to say that we won’t be cast into tribulation to be tried as Americans have never been before. To burn away the dross. To refine our faith. To see if we are indeed going to found to be good servants when he returns. To see if we have oil in the lamp or if and when our hedge is removed if we are found looking for oil to light our way through the night.