The Sun and Fog contested
The Government of Day—
The Sun took down his Yellow Whip
And drove the Fog away—

I assume 'Yellow Whip' refers to the Whig Party, as yellow was one of the colours of the Whig Party and whip and Whig are almost homonyms.

According to Franklin's dating, this was written in 1872, post-civil war, but could it be a reference to the war, with the Fog perhaps being the confederacy? I know the Whigs do not quite fit with a civil war reading (I think the Whig Party was dissolved or almost dissolved by the time civil war broke out). However, "drove the Fog away-" makes me think of war.

Or could this be a specific reference to an election won by the Whigs? And if so, what is meant by the sun's "Yellow Whip" which "drove the Fog away"?