The Kingdom of God is not now & never was nationalistic!
The question of whether Jesus would make a 'good American', itself begs the question, 'what IS a good American?' In today's day & age, a good American seems to be one who supports national pride, one who stands behind this 'great nation', even to the ignorance ( willful or otherwise ) of the evils that are perpetrated by her leaders & her citizens! A 'good American' is a patriot, put simply, 'one who loves, supports and defends one's country'!
Jesus taught, in opposition to the religious leaders of His day & even many of His own countrymen, that the Kingdom of God was not a nationalistic thing, but rather that it was a Kingdom of the heart & mind! The Coming Kingdom would not be One that would conquer through force of arms & though it would be a true Empire, it would have no certain country, or geographical base, but rather would be One that would reign over the hearts & minds of its citizens the world over!
The term 'patriot' itself comes from the Greek 'patriōtēs', 'of one's fathers' or 'fatherland'. an American patriot would thus be one who is of America, of the fatherland, so to speak! We, as Christians, are not of America; our Fatherland is the Kingdom of God, or Heaven, not these united states of America, or the American Empire!
America today has taken the stance that it is the 'city on a hill' ( with 'a thousand points of light' ) & that it is for the salvation of the world! A 'good American' stands behind America with its foreign policy of 'the ends justifies the means'; a 'good American' supports the troops in America's wars & America' practice of 'preemptive strikes'! A 'good American' believes that we must eradicate the evil ( ISIS, for instance ) & do to them what they have done to others!
Jesus, on the other hand, while proclaiming the Kingdom of God, taught instead that we should love our enemies & do good to those that hate us! Jesus taught His disciples, 'whatever you want men to do to you, do also to them' ( Matthew 7:12 ) There's nothing wrong with self-defense, in fact we should stand in the gap for those we love, but Jesus never taught His disciples to travel land & sea to build an empire & to kill all those who opposed it!
If we would be True Patriots, we need to remember our True Fatherland, Heaven, the Kingdom of God, not these united states of America & certainly not 'the good old U.S. of A.'! We must stop supporting the foreign policy of America & remembering what Jesus taught about how we are to treat our enemies, both foreign & domestic ( 'do unto others' ), realize that, not only is America NOT 'a city on a hill' ( Jesus told His disciples, 'you are the light of the world' ), as citizens of the Kingdom of God & Heaven, we may love our country & defend her against all enemies, both foreign & domestic, but ultimately, our allegiance, our patriotism belongs to our Father God, not any particular country or nation!
Charles Haddon Shank