In the link in your one post, where Donald is quoted, he provides not even a secondary source let alone a primary one.
Walt
The source for the Donald quote is: "Lincoln Reconsidered" Vintage Books, 1961, p. 81.
You prove fraud -- in the primary sources.
This is not a primary source. Go to the primary records to prove that President Lincoln did anything out of the ordinary towards fixing an election.
Ah yes, the Great Walt, setting down the rules of debate that everyone must follow. Everyone, but Walt himself, that is. Let's take a look at the example he sets:
In the 1862 election, the Republicans lost seats in Congress and barely retained their majority because of the opposite of what you say -- so many Republicans were in the army and not at home to vote.
Gee, I didn't notice any sources listed for this statement. Now why would that be? Let's see..., first you'd have to know the political affiliation of several hundred thousand soldiers; then you'd have to know how many were under voting age; then you'd have to know how many weren't registered to vote; then you'd have to know how many were not citizens and thus ineligible to vote.
After you finished up that little task, you'd have to seriously crank up your crystal ball and factor in the tendency for House seat losses in an off-year election - some from boredom and some from the inevitable disaffection resulting from administration policies in the two previous years; and finally, you'd have to calculate how may votes were lost to dissatisfaction with the management of the war.
Well, I'm sure with your talents all this is a simple matter. I'm equally sure you have scoured the primary source material down to examining precinct records and military enlistment documents to support your claim.
If my confidence is misplaced, then you're simply unwilling or incapable of engaging in honest debate.