U.S.

Plot
The plot revolved around a white-haired homeless man that dresses like Uncle Sam. He constantly had visions of American injustices (such as taking Native American lands, lynch mobs and the Civil War) while wandering around aimlessly. He eventually remembered he is Uncle Sam. He met other national personification, who give him advice, such as the Russian Bear and Britannia. He confronted and ultimately stood up to a self-satisfied and evil version of our hero. He regained his sense of his past and purpose.
Relationship to DC Comics Uncle Sam
He is stated to be Uncle Sam. It is unclear if he is the DC Comics version of the character possessing a homeless man or not. The comic shows things that support both angels.
There is evidence to support this. He sees visions of things the DC Comics version of the character would be aware of. In one of the vision, we see a Revolutionary soldier named "Sam". The DC Comics Uncle Sam was the spirit of a dead soldier Sam, who happens to manifest in the form of the national personification of America at the time.
There is evidence to disprove this. If he was a spirit possessing a bum's body, how come the spirit didn't simply take him over? The DC Comics version of Uncle Sam never interacted with other living symbols of other countries. Aside from the visions, "Sam" never displays any super powers.
References:
http://www.raintaxi.com/online/1998summer/unclesam.shtml
U.S. issue 1