By 2340, the South American Hegemony (SAH) and the North American Alliance (NAA) were on the brink of war. The SAH (formed by Mexico and Brazil, the SAH absorbed all of South America) held that the NAA (the United States, Free Quebec, Canada and the Inuit Nation) placed unfair trade restrictions and tariffs on them, and that this was the primary reason that the SAH was a "poor" nation. The NAA counted that the SAH used slave labor to undercut NAA prices, and was itself responsible for the necessary trade restrictions. As often happens when one political group needs to redirect blame for local conditions on someone other than themselves, the SAH began a media campaign between the NAA (the "haves") and themselves (the "have nots"). When the NAA failed to respond by easing trade sanctions and dumping loan money into the coffers of it's closest neighbor, the last resort was initiated, and the SAH began the war. Historians agree that the war officially started in 2341 when the SAH sent "infiltrators" across the border and set of micro-nukes in 17 major cities in the south western United States.
The NAA, after the initial shock wore off, retaliated with a low yield nuclear bombardment. This counter-strike completed the work started by the SAH's initial attacks, turning northern Mexico and most of the south western U.S. into a radioactive desert.
In 2345 rumors began to circulate indicating that the SAH was building a large military force in the nuclear wastes with the intent of launching a large-scale conventional attack into the United States. It didn't take long before the U.S. military was able to confirm the rumors through the use of recon satellites, which were only partially effective, and the much more effective hover-craft armed recon units of the NAA.
President Charles Merchante gave a presidential address on July 4th 2346. In the address he stated emphatically that the SAH military forces would never be touch NAA soil. He urged voters to contact their representatives immediately via the gov-net and insist that full military pressure be mobilized to stop the SAH before they began their invasion.
Despite the general concerns by the NAA civilians over the potential SAH threat, it is unlikely that the vote to full mobilization would have passed had President Merchante not been assassinated the following day.
The outrage over what was perceived as an SAH attempt to sew confusion into the NAA leadership was unprecedented in the NAA's short history. The vote to mobilize passed with a voter participation of more than 83% and over 92% of the voters in favor of immediate military action.
This vote of confidence precipitated one of the bloodiest conflicts in human history - The Troll Wars.
At the outset of the war, it was clear that conventional units from previous wars were not going to be effective. The environment in what was once the Southwest of the United States of America and Northern Mexico had become a nightmare. Barren expanses of desert, rocks, and dried rivers, craters and nuclear hot-spots made for a land of complete desolation. Despite this, the SAH began to build environmentally sealed cities and bases in the "Dead Zone". Armored units had to be redesigned to allow for electronics to function despite hard radiation and fierce, though infrequent, magnetic storms. All units had to have protection against heat and radiation. Infantry could not survive more than a few hours without hardened combat suits or powered armor to protect them.
As is often the case, the ability for weapons to destroy far exceeded current capacity to offer protection. Thus, while tanks and other units carried armor which would have withstood anything that a 20th Century armored force could throw at it, magnetic linear accelerators firing depleted uranium munitions, could cut through nearly anything you put on a tank.
Further, weapons technology allowed that if you could see the target clearly, it was extremeley likely that you could hit it. Unless, of course, the target had better electronic counter measures (ECM) than your targeting computers could handle. The electronic aspect of warfare allowed for the (marginal) survivability of hovercraft, which while unable to carry anywhere near the amount of protection that a heavy tracked unit could, were able to dodge quickly, and use ECM to throw off enemy shots.
Infantry units were able to survive mostly by hugging into the ground like no vehicle possibly could. With even marginal ECM, ground pounders could take ground and hold it. Small arms which could punch through more than 8cm of bi-phase ceramic-duralloy armor and portable fire-and-forget missiles gave them teeth as well, even if the small arms had comparatively short ranges.
Most individual vehicles were relatively unremarkable. Unlike WWII where subvarients of every AFV produced would keep military vehicle enthusiasts in expensive model detail kits for decades, the vehicles of the Troll Wars were mostly designed by computer AI programs to maximize their effectiveness. Variants tended to be internal, mostly in the areas of better computing equipment and software modules. Thus, any of the dozen or so variants of the NAH "Medium Tank" would outwardly look almost identical, and for the most part, would perform in accordance with the original design specs.
Then came the Trolls. The NAA did possess significant advantages in technology, and especially in software engineering. In 2347, NAA military analysts designed the first positronic AI unit - an electronic brain. While requiring a large support infrastructure, it was realized quickly that the control that this would allow over an AFV would be far superior to human crews, even with computer enhancements. Further, with no fragile humans to protect, a cybernetic AFV could withstand tolerances that would turn human crews to jelly. The biggest problem with the NAA milspec planning was what to put the cyber-brain into. No current tank, even the Heavy tanks, which weighed in at well over 300 tons and were size of small cottages, seemed like a reasonable platform. A new vehicle would need to be designed. Unlike conventional AFVs, it could be fast, extremely heavily armored, and armed with more weapons than anything short of a naval ship. The NAA military, being loaded with bureaucrats designated the initial test units as Tank: Robotic, Large in the design specs. The first TRLs off of the assembly line were not more than twice the size of a Heavy Tank. Never the less, they were more heavily armored, and carried an impressive array of a hellbore, two infinite repeaters, and a missile launcher. The hellbore was unlike any previously used armament for an AFV. The heat and radiation generated from firing it would fry even and armored crew in the vehicle. Likewise, the infinite repeaters would have been unviable simply due to the sheer amounts of ammunition used when it fired. However, with the TRL unit's positronic brain, and huge, heavily armored "body", these issues were easy to deal with.
Once proven viable in combat, the designers worked on larger and more heavily armed "bodies" for their cybernetic monsters. The Mark IIs were much more combat effective than their predecessors, carrying two hellbores in place of one. The Mark IIIs had a heavier primary hellbore, two secondary light hellbores, a pair of infinite repeaters and a missile launcher. The III was the "staple" unit of the war, seeing more production than any other mark. Given it's reasonable balance of size, armor and arms, it served the role of the U.S. Sherman tank in WWII. The largest TRL was the Mark VI. Armed with three heavy hellbores, two rapid-fire assault hellbores and a rapid fire missile launcher, this monster could take on huge numbers of enemy forces.
In addition to building larger and larger TRL units, designers also experimented with variants. The most common variant was the "-M" or Missile units. Hellbores and sometimes infinite repeaters were removed and replaced with various types of missile launchers. These units were used in "Troll Bands" - large formations of purely TRL units, as support elements. One variant of the Mark III, the "-E" or "ECM" unit had enhanced electronics making it nearly invisible on the battlefield at the expense of speed and weapons.
The name Troll was attributed to a Canadian Major in the NAA allied armed forces during the initial trials of the Mark Is in the northwest territory. Seeing these lumbering giants moving at nearly the speed of Medium Tanks, crushing any terrain in their paths, picking off target drones with seemingly no effort, he remarked to a fellow officer, "I don't know what the Yanks were planning to call them, but nothing should be that big. Those things are like trolls from some Nordic legend!" This was overheard by a "Stars and Maple Leafs" reporter who released a story two months later (published only within the military) titled, "Yankee Trolls to save the Alliance!"
Then name "Troll" stuck.