While Nighthawk was the only member of the Defenders with a direct counterpart in the Squadron Supreme (a group pf heroes from a parallel Earth), other similarities existed between the teams. Although the two would never meet, Red Guardiana Soviet crimefighter who joined the Defenders during the Cold Warhad a politically contrasting counterpart in the Squadron.
Introduced in Avengers #85 (Feb. 1971), the Squadron Supreme included a headstrong hero originally called American Eagle. Upon meeting the Avengers, American Eagle jumped to the conclusion that the Avengers were enemy Communists.
American Eagle: I think they're a bunch of Reds--or at least Commie-symps!
The Squadron Supreme limited series would provide more background about the patriotic character, whose given name was James Dore. He was in fact the second hero on his Earth called American Eagle, as his father fought crime under that alias in an earlier group of crimefighters known as the Golden Agency. The limited series alluded to a falling out between the father and son, which could account for the younger character's decision to adopt a non-political costume and change his alias to Cap'n Hawk (as seen in Avengers #148; Defenders #112-114).
After his father's death (Squadron Supreme #1), Cap'n Hawk changed his costume and codename once more, now calling himself Blue Eagle (a nod to his original name of American Eagle and, indirectly, to his early distrust of Reds! Blue Eagle died in combat against the Redeemers, a band of heroes and villains who challenged the Squadron's Utopia Program (Squadron Supreme #12).
This image of Blue Eagle (left) comes from the deluxe edition of The Official Handbook of the Marvel Universe. Interestingly, the original entry for the Squadron Supreme in TOHOTMU #10 (Oct. 1983) listed James Dore as Condor, a codename he never used in the comic book stories. The preliminary design for Condor resembled the costume the character would wear as Blue Eagle.