This meditation is part of a dialog on Patheos.com about the question, "So, when does patriotism pass over into idolatry?"
Idolatry is often subtle. I've never walked into a Church to see the cross replaced with a golden calf. It's not that blatant. Idolatry replaces God with anything that is less than God, even if that thing is pretty good.
I would define patriotism as the love of country and to desire and work for its good. It is a good thing. Patriotism passes into idolatry if Christianity is reduced to a means of achieving the good of country, or love of country comes to mean the same thing as love of God and neighbor.
There are two primary ways we can slip into idolatry: through theology or fervor. Our theology, for starters, needs to distinguish between what it means to be an American citizen and a Christian; between the hope of Christ and the will of God for America. It needs to say how we love God and neighbor first and still love country.
When it comes to fervor, we can't allow our political passions to cloud Christian discernment. For example, Christians should be concerned about our national security. But, that does not mean anything our country does in the name of national security is Christian or moral. Christians should be concerned about the poor. But, that does not mean anything our country does in the name of helping the poor is right. God desires America to be secure and just (as God does of the whole world), but Christianity is not to be reduced to something useful merely to these ends.
Idolatry can creep up on you. For personal accountability, I try to be in regular contact and relationship with Christians who share different political opinions, especially Christians living in different countries. Having close friends and family who passionately disagree with my politics has helped me discern between my political fervor and Christian conviction. Having friends whose patriotism is directed at a different nation-state, but who still share my faith, has helped me distinguish between my love of God and my love of country.