'68 Democratic primaries: why did Kennedy win South Dakota and Nebraska?

[RI]

I can't speak for South Dakota in 1968, but I know Kennedy campaigned pretty hard in Nebraska and did quite well with the rural Catholic vote. I believe RFK won Omaha, which combined with the rural vote is a guaranteed win in NE. McCarthy won in Lincoln and in a few rural areas and I have no explanation why on the later. FWIW, Ted Kennedy won several counties in the 1980 primary in eastern NE over Carter. I think Ted may actually have won South Dakota that year. 

Does anyone have a Kennedy/Carter '80 primary map of the states?

You know, there is a thread just a few down that is all about primaries...

[RI]

I just added South Dakota's 1968 Democratic primary to my primary thread, and it appears that Kennedy absolutely dominated among the Native American vote, winning over 90% in Shannon County, plus he won generally in all areas of the state. RFK also won Brown (Aberdeen), Minnehaha (Sioux Falls), and Pennington (Rapid City) Counties, which contain a large chunk of South Dakota's vote.

For the record, RFK won South Dakota by almost 20 points; Kennedy received 49.5% to LBJ's 30% and McCarthy's 20.4%.