As for what Kirby would say to Englehart...well, that's hard to say. Kirby's political perspective is very weird at times. One of the things that strikes me about the Fourth World comics, NEW GODS in particular, is that it doesn't seem like something an American would make. The idea of two superpowers dueling over a country in between is something you'd imagine coming out of a smaller, non-aligned country.
I've always thought Kirby's politics were Democrat or liberal if not exactly left wing but so much of Kirby was also an ancrhonism by say, 1980.
Googling the subject of course turns up Mark Evanier on Kirby:
"Basically, he thought Captain America was bigger than any one writer's momentary politics, which is why he didn't inject his own into the stories he wrote."
He then goes on to five a sketch of his politics in an articlem part of which reads as follows:
Jack's own politics were, like most Jewish men of his age who didn't own a big company, pretty much Liberal Democrat. He didn't like Richard Nixon and he really didn't like the rumblings in the early seventies of what would later be called "The Religious Right." At the same time, he thought Captain America represented a greater good than the advancement of Jack Kirby's worldview. During the 1987 Iran-Contra hearings, Jack was outraged when Ollie North appeared before Congress and it wasn't just because North lied repeatedly or tried to justify illegal actions. Jack thought it was disgraceful that North wore his military uniform while testifying. The uniform, Jack said, belonged to every man and woman who had every worn it (including former Private First Class Jack Kirby) and North had no right to exploit it the way he did. I always thought that comment explained something about the way Kirby saw Captain America. Cap, obviously, should stand for the flag and the republic for which it stands but — like the flag — for all Americans, not merely those who wish to take the nation in some exclusionary direction. In much the same way, one of the many things Nixon had done that offended Jack was an attempt many decried, on the part of that administration, to usurp the American flag as a symbol of support for Richard Nixon.
Jack's 1976-1977 stories of Captain America — the ones where he had near-complete control — show very little evidence of his own political beliefs of the time. He felt strongly about many things happening in the world at that time, especially various battles and hostage situations relating to Israel, but he chose to keep his hero above those frays and to deal more in the abstract. Captain America made his greatest statement by wearing the flag with pride and by triumphing over all forms of adversity. To Jack, it was the great thing about the American spirit: That it was born of gutsy determination and, as with any good superhero, compassion for all. Some of the storylines he talked about but never had the chance to put into print would have reinforced the idea that Captain America was greater than any one man...including those who created his adventures.
http://www.povonline.com/notes/Notes031005.htm