This may just be because I'm a Mainer, but I think Ed Muskie would be the nominee. He was the favorite entering 1972 (he won both Iowa and New Hampshire), and it's likely because of the Nixon smear campaign's "Canuck Letter", which sparked the "Crying Speech" on that snowy day in front of the Manchester Union Leader building in Manchester, NH, at which point killing any chance Muskie had of ever being president, unfortunately.
Assuming Nixon resigns in 1972, and Agnew doesn't run, I think that there might be general disgust with the GOP. Ed Muskie wins the nomination, because the "Canuck Letter" is never published. George McGovern is his running mate to appeal to the more radical of the party, as Muskie is relatively centrist.
The GOP chooses George Romney with John M. Ashbrook as his running mate. I know this is kind of going against what the entire topic was about, but here is what I think it would be:
Edmund Muskie (ME)/George McGovern (SD) - 334
George Romney (MI)/John M. Ashbrook (OH) -204
My first map posted! Anyway, perhaps I exaggerated Muskie's prowess over Romney. I don't really care, though, cause Muskie is awesome.
Vermont and NH were both Republican strongholds back then, as was Indiana. Illinois was a swing state. That's what I know, at least. I don't think the margins would be so wide.
