Simply put, the NCR has no battle plan. More complexly...
The Legion is running a basic gambit which focuses on breaking your opponent rather than annihilating them, this is ineffective for late stage conquest but early on is more effective than wiping them out, much more. Indeed at the point of the Legion meeting the NCR their tactic is the best available for reasons I'll explain later. Let's look at what they would actually do.
This all assumes the Courier lies dead, simply because it's too complicated to incorporate a godly individual with no set allegiance.
OK. The Legion has actual bases at Nelson and Cottonwood Cove across the river, the rest of their forces are to the east of the dam. They have an allegiance with the Khans who will aid them. The Fiends are presumably supplied by them (ties to Khans, general objectives) and if not, by someone targeting the NCR. The Omertas are the final secondary group to join CL.
Without courier intervention the BoS remain isolated, enclave doesn't intervene, Boomers are isolationist, White Glove society is aside, securitrons are not upgraded, The chairmen are neutral/not involved.
So, after taking Nelson, hitting the NCR supply lines, destorying Searchlight and burning Nipton to the ground the Legion prepares for it's actual assault. The average NCR soldier is, by this time, terrified. Between the horror stories on the radio waves, the loss of various camps, the constant pressure and the impending fight many will consider desertion, likely few would.
As the battle initiates the Legion's plans become clear. From Cottonwood cove they attack deep and hard, pushing on any location useable as a rendezvous point. Novac, Mojave outpost etc. The Nelson troops hit Forlorn Hope's remaining men, annihilating the camp. The Fiends attack McCarran and succeed in overrunning it (or at the very least, causing incredible damage), without the monorail any survivors are cut off. The Khans harass any groups moving behind the NCR's line. The Omerta's begin their assault, taking the fight straight to the strip. I presume they will ultimately lose but the damage would be severe, they are well armed and the attack is a surprise, House too concerned with other matters, the families bickering and so on. The dam would fall without a hitch, Oliver's approach is nothing short of a suicidal rush at an enemy who knows no fear. Genius.
With the dam gone they would fall back to Helios One, if the BoS do not stay hidden the NCR would be hit by them, presuming they do the Legion would simply force them out.* Camp Golf would be the last major NCR base but it's proximity to the dam, with Legion forces from the north (having easily overrun the few refugees at Bitter Camps), east and south (whatever could be spared from Nelson) it would be a suicidal stand or a bugout. Saddeningly I get the feeling this is where Hanlon would make his last stand, against overwhelming opposition. Nonetheless, it would fall, the Misfits are useless, the general standard low. The rangers are tough and would take their toll but without support...they are men, a man can do only so much. Golf would fall, the NCR would be in full retreat. The strip is no haven for them, between shut out communications, the omerta's riot, the Kings' no doubt being even more aggressive towards the NCR and the transport from McCarran down they would be best to move on past. McCarran would be either the Fiend's or a stone tomb. Isolated, it would become a fortress in the storm, besieged or simple assaulted until it fell dependent on who was in charge and how much power the Legion had left.
Forlorn Hope is gone, the various ranger stations would debug and fall back to support the retreating main body. Helios One down, Bitter Springs down, Novac under pressure or overrun, the Khans to the west, nothing but desert to the south. The only escape is southwest, back to the NCR's homeland. The NCR army would be routed.
Guessing I would say McCarran would be taken to a man Hsu and his men gone, Bitter Springs would be hit hard and scattered but not exterminated. Golf, the standard troopers would flee, many rangers would not, Hanlon and his men would be killed. Forlorn Hope wouldn't stand an attack at full strength, much less with the distraction of the dam. Exterminated. Novac would likely be overrun or it's defenders forced to retreat. Again, saddeningly I could see Boone finding his death there.
The NCR would be gone. The Strip an easy target, already weak, now crippled. The Boomers would be left until Caesar knew what to do with them (I foresee a slow campaign against them, continual probing until a means is found, the service tunnel would be found, they would be killed). The BoS would be found and killed in some manner, either by forcing their way in or if they feel tactful, sealing them in their tomb.
eta a tl;dr
They would lose all major bases and be forced to rout, survivors (rangers notably) would be pulled to defend their rear as the bulk pulled out.
Think of it like a man with 5 arms. Each grips a desk. Attacking one at a time, the other arms can beat back the attacks, damage is done but nothing horrible. Attack all 5 at once with enough force and they will recoil, unable to regain a purchase they would retreat to the body. This is the NCR. An attack on all fronts removes their holds from under their feet. The escape is left for them.
Without the Courier there is no other turnout, the Legion's attack is a classic tactical manoeuvre designed to rout. It would succeed. Hsu and Hanlon, the only two officers worth a damn, would probably lose their lives too. As would innumerate others, House among them once Caesar grew bored of him, given his attitude to CL I doubt he'd entertain the man...
yes But there is Ranger station Delta You act like the NCR wouldnt catch whiff of there moves and tactics. The NCR would try to devise a plan to try to stop this collation of forces or prepare themselves for the war to happen. Another thing is How are the fiends more powerful than a NCR trooper Fiends/Raiders are not suppose to be powerful and have the weapons they have. I do not believe one thing that the Fiends would devastate the Camp mccarn if anything the NCR troops and people stationed there would wreck them. Raiders in F3 were easy to kill and didnt have adequate weapons to fight either. I dont get how they go from a person barley armed to a person armed to the teeth with all kinds of weapons and a Base.
BTW we are getting off topic i didnt want this to turn into a CL vs. NCR debate here.
» Tue May 12, 2009 1:51 pm 
