there is a logic to this definition of the North, but there's nothing solid about it in the contemporary context. For a while these states were solid Republican, but even then not at the percentages that the Deep South was solid Democrat.
Yes indeed.
By 1892, Democrats were getting as much as 45% of the vote in formerly die hard Republican states like Massachusetts, Rhode Island, and Pennsylvania and were regularly very close in GOP states like Ohio and New Hampshire while the South was only becoming more and more Democratic. If Cleveland had just a few points shift towards him on Election Day 1892, he could've won a massive EV landslide. Whereas, Roosevelt only managed a slight EV landslide while winning 56% of the popular vote.
Granted, the "Bryan era" would drag down percentages in the North, but by Wilson's re-election in 1916 things were back to what they were before.
So yes, North definitely wasn't solid.
The South, however, showed no signs of cracking. In fact, Republicans did BETTER in the South in the late 19th Century than they did in the early 20th (with massive exception of 1928). It was when Bryan was the Democratic nominee on a regular basis when states below Mason Dixon line started voting in the 80%-90% range.
Now THAT is solid.
Granted, there were some "South" states that did vote Republican in certain circumstances, but not as much as the "North" states would vote Democratic in certain circumstances.
Of course it needs to be said that "the solid south" was a bit of an illusion. States in the deep south we're only solid for certain white males who voted regularly at that time. Had blacks been able to vote, many states in the deep south might have been competitive, since (pre-great migration) many of them were close to 50% black.
On the other hand, you could say the deep south is still solid by just looking at the white vote. If you factor out the votes of black voters and the miniscule amount of registered Hispanics and Asians, you have AL and MS voting in the high 80s for McCain, Georgia at around 75% McCain, SC around 72% McCain, and Louisiana around 85% McCain.
