This would not make the U.S. a theocracy. It would merely require the government to adhere to the bedrock principles upon which America was founded. This country was founded as a Christian nation. That was well understood until around 1960. We need to return to the values that made us great.
There's nothing in the Constitution that prevents the Federal government from endorsing a religion. Nothing whatsoever. It's not in there. What is there is this:
Congress shall make no law respecting an establishment of religion,Note the phrase "an establishment of". "Establishment" isn't a verb, it's a noun referring to something that has been established. It refers to an established group, i.e. to a denomination or collective formally organized entity. In other words, the Federal government is prohibited from creating legislation that sponsors, endorses, funds, or legally constrains one religious denomination to benefit another. Rather, it is supposed to step back and allow all denominations to exist within the Commonwealth, provided they act within the laws of the land.
or prohibiting the free exercise thereof.
More importantly, however, I believe there is nothing within the Constitution that prohibits our Federal government from officially recognizing, acknowledging, and declaring fealty to a deity or Lord worshiped by the Republic's citizens. In fact, I believe the Federal government (with the caveat that the vast majority of the states, and people that it represents, agree to such) ought to formally acknowledge the risen Jesus Christ, Second Person of the Triune Godhead, as it's Sovereign Lord and King of the United States of America, via an amendment to the Constitution. If the citizens of the United States of America are (by overwhelming majority) of the Christian faith, then IMO that's what I believe our constitutional, representative Republic ought to do.