Eh, it's New Jersey, there are a couple loonies up north who have drunk the "civil war wuz all 'bout STATES RIGHTS n' had nuthin' to do with slavery" kool-aid, but most conservatives are normal.
But the key point is that Lincoln became a nationally known celebrity overnight precisely because he lost the Senate race by a razor thin margin and WON the popular vote during the era when that didn't affect the outcome.
Had Lonegan or Oberweis been running back then, they would have ran some nasty attack ad accusing all the other abolitionist Republicans of being "part of the pro-slavery establishment", and they would have immediately sought office again after getting crushed in the primary (of course, it would be the fault of the "pro-slavery establishment" that they lost). Alternately, if they had no real competition and won the nomination, and they would have shot themselves in the foot debating Douglas, and the guy would have won re-election in a walk. (which of course would have also been the fault of the "pro-slavery Republican establishment")
I don’t think primaries existed yet. ;d
They are another “evil” reform like the wicked 17th amendment.
I have to say though in some States like Utah (where you can’t get on the ballot without going through the convo) and MN (where opposing the party convo’s nominee is taboo) using the party convention process seems to be mostly positive. It sure as hell wouldn’t work well in Illinois though.