That's a good one, Thucidides...
But I think you've overlooked something...
First, what we do agree on, is that neither JFK nor Reagan could breach very far... both good communicators, but far too agressive and, like you said, neither of them have that Roosevelt "I'm bending the laws here, but it's OK, because I'm a Rossevelt... and my bending rules generally makes sure America doesn't break!" air about him.
And that's what I think's been overlook, and something I did intentionally-
The Roosevelts, Teddy and Franklin... as Germany and Austria, they're natural allies, and as family, even more so.
Can you IMAGINE THAT ALLIANCE? Germany-Austria's usually a great one in any case, but with the ROOSEVELTS at the helm...
Teddy, Franklin, there's so much war skill (Teddy first hand, Franklin from the Oval Office) and so broad an appeal (a Republican, a Democrat, both New Yorkers but both with strong ties to rural America, both huge progressives...)
TR/FDR would be a MONSTER alliance.
And that presents something interesting... what does Lincoln do? FDR's not going to bail on TR, and likewise TR with FDR, so even if Lincoln took out JFK (talk about ironic) and Reagan fell, Lincoln'd still need to find a way up the middle, through the Roosevelts.
And if it boils down to Lincoln vs. the Roosevelts, and Jefferson and Washington are left...
WHO sides with Lincoln then? Not the Southerner Jefferson with his masses of slaves... nice guy (relative to the time) but still, he's not going to go against his party AND principles... and as Italy, he's not in an agressive spot to do fight such a war, anyway... he's not beating Washington...
Which essentially means if Lincoln were to win he'd have to convicne ANOTHER slave holder (albeit a great man who freed his slaves in his will) and Southerner, Washington.
And wouldn't THAT be the biggest political war in US history- arguably (I'd argue for it) the four greatest Presidents going two vs. two...
Washington and Lincoln vs. Teddy and Franklin Roosevelt! :D