In general, you confuse the process of negotiations with the word for the outcome. The negotiations are where the deal is made, the compromise is the deal made. You will never, ever get more than you asked for in the first place in a compromise, that is what makes it a compromise. Getting more than you orinially wanted is called 'winning the negotitations'. And that is not only the goal of negotitions, it should remain the goal, because to offer capitulation when you should be making demands is to be derelict in the duty to negotiate. It is not negotiation to say 'we already know what the opponents want and we already put that in the deal'. That's not negotition, that is dictation to the opponents. It is neccessary to make them come take what they want, and to go take what we want as well.
To end with a compromise, the negotiations must be honest and true, each side taking strong stands for their own goals. Trying to do the other side's work for them is not only unworkable, it insults the other side, who will just up their game and ask for more.
Many career fields function under negotiated contratual deals. Finding compromise via negotiations is not at all unique to DC. It is in fact the currency of most business, certainly of my business. Millions of Americans know how to hash out a deal with difficult opponents who must be molded into a partnership for a time. When I look at how the DC crowd carries on, I am grateful that my business knows how to actually negotiate and actually make a deal which is acceptable to all parties, lacking in 'punishments' for one side or the other, laden with benefits for both sides and all others.
Only a great deal which makes both sides content is a good compromise. To reach a good compromise, negotiations must be made until both sides are content.
And at times, this process fails to deliver results. As it did in Lincoln's time, some 'compromises' are just bad deals which could never work for neither side is content. The idea that a good deal makes both sides unhappy is the opposite of the truth.