Final answer:
Stephen A. Douglas was the presidential candidate in 1860 in the West who had previously run against Abraham Lincoln in Illinois.
Step-by-step explanation:
The presidential candidate in 1860 in the West that had previously run against Abraham Lincoln in Illinois was Stephen A. Douglas. Douglas, a Democrat, ran against Lincoln in the Senate race of 1858 in Illinois, but was defeated. However, in the 1860 presidential election, Douglas was again the Democratic nominee and competed against Lincoln, who represented the newly-formed Republican Party.
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