3. "Secret Empire" Captain America #169-175
This arc (which you could argue goes back even further than #169) involves an evil Illuminati-type group known as the Secret Empire, who slowly turn the country against Captain America and the Falcon. Our heroes slowly build their way back to proving themselves heroes to the world, but they are shocked to learn just how far the Secret Empire's influence had grown in the United States...
Steve Englehart wrote this gem while the country was in the wake of the Watergate scandal, and it truly shook Captain America to the breaking point, as he gives up his identity in the wake of this storyline. Sal Buscema delivered the artwork.
Go to the next page for #2-1!