I was looking for a way to improve on the reliability of gaining (or losing) national morale. I think that in a lot of cases it is too hard to gain back, as even spectacular victories result in very little NM gained, while sometimes minor defeats result in lots of NM lost.
Anyway, here's the plan.
Every turn (15 days) your NM goes down 1 point automatically. Regardless of choices of draft or finances, battles, etc. Basically, the longer the war goes on, the more your NM declines (even while doing nothing). This means that the player must take an active role to stop this drain. (To let you know, I am not applying this to the AI, since it probably cannot handle it).
How do you regain this lost National Morale? Well, other than battles I plan for a few options, depending on who you are playing as...
--USA--
1. One way in gaining National Morale is to strike into the South and capture critical bases, depots and cities. If you attack and capture a city with a certain number of troops (to stop raiding parties from achieving this goal) you get a one time boost of national morale (if you lose the city, and recapture it you gain no extra boost).
However, this 'boost' changes over time. The longer that the game goes for, the less of a gain you get for the capture. For example, say you have the following territory of Fort Donelson (which is near the border of the USA-CSA).
1861 Capturing Fort Donelson gains the USA a net of 4 NM points.
1862 Capturing Fort Donelson gains the USA a net of 3 NM points.
1863 Capturing Fort Donelson gains the USA a net of 2 NM points.
1864+ Capturing Fort Donelson gains the USA a net of 1 NM point.
For a city that is futher in the CSA (say Atlanta) the decline would be a lot less, and indeed capturing it in 1861 would be a major victory and represented as such.
1861 Capturing Atlanta gives the USA a net of 15 NM points.
1862 Capturing Atlanta gives the USA a net of 12 NM points.
1863 Capturing Atlanta gives the USA a net of 10 NM points.
1864 Capturing Atlanta gives the USA a net of 8 NM points.
1865 Capturing Atlanta gives the USA a net of 4 NM points.
So, here you see that there is a drive for the USA to make an effort to attack Confederate objectives early and not just to wait for the best possible moment (i.e., when you have overwhelming numbers in late 1862 to start your attack).
2. Another way that National Morale affects the Union is by losing a critical city or region.
There are a few border or cities near border states that are critically important due to depots, rail links, or possibly inciting pro-southern sympathies (depending on the city).
Losing one of these cities to a concentrated CSA attack would be a heavy blow, especially as the war drags on. Take Baltimore MD.
1861 Losing Baltimore has the USA lose 4 NM
1862 Losing Baltimore has the USA lose 6 NM
1863 Losing Baltimore has the USA lose 8 NM
1864+ Losing Baltimore has the USA lose 10 NM
So, the longer the war goes on, the loss of a friendly city will have greater negative impact on the nation as a whole (symbolizing that the war must not be going well after all these years due to the loss of these cities). Hopefully this will keep the USA player interested in guarding their supply lines (as they historically were inclined to do).
3. 'Liberated Cities'
Losing a 'liberated city' (i.e., one where you gain NM points in situation #1) will be a major setback. Imagine if the CSA retook Vicksburg or Fort Donelson after the victories there?
This will encourage USA players to garrison the NM cities that they have taken from the CSA, otherwize they will lose any NM bonus that they gained in its capture.
Say the USA captured Fort Donelson in 1862, gaining 8 NM, and the CSA retook it, the USA would then lose 8 NM (even if they retook the fort, they would not be able to gain anymore NM, since the events will only trigger once).