On the Abraham Lincoln was conservative claim.

[TDAS04]

It's hard to define where 19th century politicians would fit on the modern liberal/conservative spectrum, for obvious reasons.

I won't claim Abraham Lincoln was exactly the modern liberal, but some Republicans argue the opposite extreme that the parties haven't changed in any meaningful way since Lincoln's time.  If someone claims that Lincoln might be a modern conservative if he were alive today, that's fine, but I do think he might have been a moderate liberal.

To this day, some Republicans claim that Lincoln perfectly embodies the conservative ideal of capitalism.  Lincoln was born poor, rose from rags by pulling himself up from his bootstraps, no government help...  That doesn't necessarily mean that he would never of supported any safety net for the needy over time.  Who knows, maybe he would have been sympathetic to the poor, as he was born poor, and the means and prospects of rising up are not the same today as they were back in the 1800s.  

Obviously it makes no sense to discuss Lincoln's position on gay marriage or abortion or marijuana.  We can't say he opposed the death penalty, because he did permit some executions and it wasn't much of a debate back then.  However, moments where Lincoln had to decide whether or not to allow executions to proceed reveal that he was a pretty soft-hearted man (even while he was strong enough to lead America through the bloody Civil War).  He disliked approving the executions of young men who deserted in war, and he granted clemency to many of them.  He even disliked killing animals and he did not enjoy hunting.  If Lincoln was a conservative, he must have been a compassionate conservative.  Not that temperament or compassion necessarily determines political ideology, but it's hard to imagine today's tough-minded Trumpsters and tea-partiers not rolling their eyes at many of Lincoln's merciful tendencies.

It's true that it's tricky to determine how politicians from the distant past fit on modern political spectrums, and it can seem pointless.  However, the OP had a point in starting this thread.  After all, many Republicans claim that they're still the party of Lincoln in every sense, and that the party of Trump is exactly the same as it was in Lincoln's era.  Many of today's Republican who support Trump are in fact neo-confederate types who hate Lincoln, while many others are just ignorant enough of history to think that Lincoln would have been a Trumpster.  After all, they're both Republican, right?