Absent the rebellion, and had the existing slave states all hung together, then it would have taked 46 states to pass constitutional amendments the slave states opposed. That's a total of 61, if your math is weak. I guess they would still be working at it, huh?
Oh, wait -- they did that, didn't they? Direct election of senators, and then the income tax, and then woman suffrage and Prohibition. Yup, that all worked out well, don't you think?
Take a look at the ratification of those amendments and you'll notice that southern states were early and enthusiastics supporters of the 16th and 18th Amendments, and late out of the gate on the 17th and 21st. Reluctant support of the 18th would be, I imagine, to the southern preference for denying the vote to people.
If Lincoln hadn't started and won the Civil War, we'd probably have had something like 54 instead of 48 States in "the lower 48".
And still not enough to end slavery until Hawaii.
You keep trying to walk this idea past us, that Lincoln would have confined himself to constitutional measures. When clearly that was not his m.o. -- as witness his escapades with West Virginia and Nevada, and his suppression of Maryland and Missouri.
Lincoln was a machine politician who liked the steel fist. He played with the gloves off, and he could have given lessons to all those other machine pols you're so proud of.
"Rape" was the right word.