Were Lincoln a candidate today, I doubt his views of the afterlife would be well-recieved by his party. But, then again, perhaps the anti-secularist or anti-athiest elements of the electorate are exaggerated.
I'm yet to encounter nearly a fraction of the left 'outrage' that Manton et. al. claim exists over these 'Dog Whistles'. If anything, it's a sensationalised issue, with the perpetrators being fringe left in the media and fringe right responding to nothing more than a caricature of the left. I've never heard anyone even use the term 'politically correct' other than to chastise it IRL.