Lincoln starts with a dry history of the Constitution aimed at showing that the founders opposed slavery's expansion, the policy of the 1860 Republican party.  He then characterizes the South's demand that slavery expand as an aggressive violation of the Constitution, and, worse, a threat to the North to submit to slaveholders' demands or face war.  He ends by challenging his audience to stand up to the South regardless of the consequences  The excepts below follow Lincoln from legalese to an emotional appeal to nation, self-respect, and doing what's right.

In the context of the present, substitute the rule of law for the intent of the founders on slavery; GOP manipulation and corruption as illegal acts and the GOP agenda as a demand for "rule or ruin"; and close with a call on Democrats to stand up to the bullies in the name of the law, morality, and self-respect and you've got Lincoln in 1860.  Not a bad case to make.

Lincoln at Cooper Union:
"What is the frame of government under which we live? . . . This is all Republicans ask - all Republicans desire - in relation to slavery. As those fathers marked it, so let it be again marked, as an evil not to be extended, but to be tolerated and protected only because of and so far as its actual presence among us makes that toleration and protection a necessity.

A few words to the Southern people . . .
It was not we, but you, who discarded the old policy of the fathers. We resisted, and still resist, your innovation; and thence comes the greater prominence of the question. . . .  

When you make these declarations [that the South will secede if the federal government limits slavery's expansion], you have a specific and well-understood allusion to an assumed Constitutional right of yours, to take slaves into the federal territories, and to hold them there as property. But no such right is specifically written in the Constitution. That instrument is literally silent about any such right. We, on the contrary, deny that such a right has any existence in the Constitution, even by implication. . . .

Your purpose, then, plainly stated, is that you will destroy the Government, unless you be allowed to construe and enforce the Constitution as you please, on all points in dispute between you and us. You will rule or ruin in all events. You will not abide the election of a Republican president! In that supposed event, you say, you will destroy the Union; and then, you say, the great crime of having destroyed it will be upon us! That is cool. A highwayman holds a pistol to my ear, and mutters through his teeth, "Stand and deliver, or I shall kill you, and then you will be a murderer!"  . . . the threat of death to me, to extort my money, and the threat of destruction to the Union, to extort my vote, can scarcely be distinguished in principle.

A few words to Republicans. . . Their thinking it right, and our thinking it wrong, is the precise fact upon which depends the whole controversy. Thinking it right, as they do, they are not to blame for desiring its full recognition, as being right; but, thinking it wrong, as we do, can we yield to them?

Wrong as we think slavery is, we can yet afford to let it alone where it is, because that much is due to the necessity arising from its actual presence in the nation; but can we, while our votes will prevent it, allow it to spread into the National Territories, and to overrun us here in these Free States? If our sense of duty forbids this, then let us stand by our duty, fearlessly and effectively. Neither let us be slandered from our duty by false accusations against us, nor frightened from it by menaces of destruction to the Government nor of dungeons to ourselves. LET US HAVE FAITH THAT RIGHT MAKES MIGHT, AND IN THAT FAITH, LET US, TO THE END, DARE TO DO OUR DUTY AS WE UNDERSTAND IT."