The Warden Clans were those Clans who adhered to the Warden ideology in Clan politics. The essence of the Warden ideal was that Aleksandr and Nicholas Kerensky had never intended for the Clans to reestablish the Star League by force or conquer the Inner Sphere, but to remain aloof from its corrupting influence while standing ready to intervene should the Inner Sphere require saving from an existential threat.
The Wardens succeeded for decades in preventing the Crusaders from spearheading an invasion of the Inner Sphere until an unforeseen event in 3048 finally resulted in a Crusader-led assault upon the Great Houses. The ultimate failure of that invasion, eventually defeated in accordance with the Clans' own laws, left the Wardens temporarily triumphant before events after 3060 saw the Crusader-Warden divide rendered moot by a permanent rupture between the Home and Invading Clans.
The Warden philosophy was adhered to by all of the Clans throughout the Golden Century, though the term 'Warden' itself didn't come into use until the Crusader ideology arose in opposition to it. Derived from a passage in Nicholas Kerensky's diaries - “to ward the Inner Sphere from all outside forces until that time when the Star League is reborn” - this doctrine mandated that the Clans' superior culture was to remain isolated from potential corruption and the barbarian influence of the Great Houses, only to intervene if an 'outside threat' were to menace the Inner Sphere. The Wardens never provided a definitive answer as to what such an 'outside threat' might be, but some suggested nonhuman enemies from beyond known space while others spoke of countering a human tyranny so vile that it transcended the bounds of decency.
A gradual change in the Clans' political landscape first became noticeable in the mid- to late 2900s as the Golden Century transitioned to the Political Century. The increasing disunity between the Clans, coupled with support for a return to the Inner Sphere from the civilian castes who suffered most in the harsh worlds of Clan Space, led to a new ideology arising: that of the Crusaders. Decades of Grand Council neutrality on the issue finally ended in 2980, when the first Clan to declare itself for the new movement, the Jade Falcons, presented a formal proposal for an invasion of the Inner Sphere.
Stemming the Crusader Tide
The Falcon motion was defeated but the invasion debate had now become too prominent to ignore. As a result the Wardens spent the next seven decades fighting an ultimately losing battle against the rising support for the Crusader cause. The first measure they supported was the formation of Intelser; intended to rectify the lack of solid information on the Inner Sphere, this organization's members infiltrated several Periphery states throughout the 2980s. This second-hand information proved of limited value and Intelser's failure would provide a compelling argument for the Warden's next move.
By 3000 the Crusader cause was on the verge of triumph as pro-invasion support reached overwhelming levels. But when Khan Nadia Winson of the Ghost Bears put the motion to the Grand Council, Khan Kerlin Ward of Clan Wolf pulled off a victory for the Wardens. Arguing that the lack of useful intelligence made an invasion too risky, Ward convinced most of the Grand Council to support the formation of a mercenary unit intended to remedy this defect: Wolf's Dragoons. The Dragoons would serve each of the Great Houses and report back on their strengths and weaknesses, but this odyssey would take several years - possibly up to three decades - to complete. Despite protests from the Jade Falcons and Smoke Jaguars, and rebellious elements of Clan Ice Hellion nearly launching their own solo invasion, the Wardens had successfully staved off a Crusader assault upon the Inner Sphere for years to come.
Even with the apparent defection of the Dragoons around 3019 and rumors of the new Federated Commonwealth superstate threatening to dominate the Inner Sphere, the Wardens, now led by Ulric Kerensky, still managed to prevent a Grand Council 'go' vote on the invasion throughout the mid-31st century.  But the Crusaders found a charismatic and fanatical spokesman of their own in Khan Leo Showers of the Smoke Jaguars, and during this era Showers and his allies steadily chipped away at Kerensky and the Wardens' support base in the Grand Council. Nonetheless, the Wardens managed to thwart Showers at every turn, until 3048 when fate delivered him the intelligence coup he needed to tip the scales.
After secretly interrogating the Outbound Light's personnel, Showers then presented his findings to the Grand Council. Swayed by his arguments that the Steiner-Davions were on the brink of recreating a new Star League without the Clans' input, and that the Clan Homeworlds themselves would be discovered and possibly attacked, the pro-Warden bloc collapsed, leaving only Clan Wolf to oppose the invasion. The Wolves narrowly lost a Trial of Refusal over the vote and with Leo Showers' subsequent election as ilKhan to oversee Operation REVIVAL the Warden cause appeared doomed.
After Clan Wolf was added to the invasion force, however, the Wardens would receive an unexpected change of fortune. Khan Kerensky ensured that the Wolves became the most successful of the Invading Clans during the first year of REVIVAL, outdoing the Crusaders in their own cause and making it likely that Clan Wolf would seize Terra first, resulting in a Warden ilKhan. Sensing as much, ilKhan Showers tried to stymie the Wolves' advance and eventually arranged for a Grand Kurultai, presumably as part of this effort. Whatever Showers intended would remain unknown, as the Rasalhagian convoy carrying their Elected Prince blundered into the Clan fleet at Radstadt, and Showers was killed when Tyra Miraborg rammed her fighter into the Dire Wolf's bridge.
Ulric Kerensky's subsequent election as ilKhan, intended as a Crusader bid to replace him with a sympathetic Wolf Khan and sideline him as an opponent, backfired when instead the Warden Natasha Kerensky succeeded him to the post. The addition of Clans Nova Cat and Steel Viper to the invasion force also aided Warden goals; while the Cats were Crusaders and the nominally Warden Vipers were also pro-invasion, each shared an invasion corridor with a historic enemy and the resulting conflicts further undermined the Crusaders' two leading Clans. Meanwhile the Ghost Bears were also shifting towards a Warden standpoint.
When the invasion resumed in late 3051 the Crusaders continued to struggle - and suffered a humiliating defeat on Luthien - while the Wolves again outstripped the other Clans in their pace of conquest.
The Refusal War
The Great Refusal
During the eve of the Great Refusal, the ilKhan Lincoln Osis and the rest of the Invader Clans tried to force the remaining homeworld clans to fight against the Inner Sphere's reformed Star League Defense Force led by Victor Steiner-Davion. This plot would be prevented by Clan Ghost Bear who announced that they have abandoned their Crusader ways and embraced the Warden philosophy. The Ghost Bears would withdraw from the Great Refusal. The other Warden Clans would follow suit and chose not to participate in the Great Refusal, leaving the remaining Crusader Clans to fight the Inner Sphere on their own. With the defeat of the Crusader Clans and the death of the Smoke Jaguars, the Warden philosophy would be seen as victorious.
Post-Wars of Reaving
After the Wars of Reaving, the remaining clans saw that the old Crusader-Warden split was tainted. So the viewpoints died off and in its place was the Bastion-Aggressor philosophy, both espousing the invasion of the Inner Sphere.
The Warden philosophy was known to have an effect on those who supported it. First, it was made as a way to oppose the Crusaders, then it divided further between the Invaders and Home Clans (as the Home Wardens and Invading Wardens). After the Wars of Reaving, the Home Warden Clans replaced their philosophy by calling themselves the Bastions. This philosophy, like the Wardens, did espouse the idea of isolating themselves from the Inner Sphere. But unlike the Wardens who saw themselves as protectors of the Inner Sphere, the Bastions believed that the Inner Sphere was corrupted by taint and sought isolation for themselves until a new invasion was underway. The Invading Warden Clans in the Inner Sphere now concentrate their efforts towards protecting the Inner Sphere.
Though its membership changed over the years, Clans Wolf and Coyote led the Warden bloc from its beginnings until after the Refusal War, when the Wolves were split between a reborn Crusader-dominated Clan Wolf and the Abjured Clan Wolf in Exile who continued to support the Warden cause. Clan Goliath Scorpion traditionally supported the Warden cause as well, while the majority of Clan Cloud Cobra's cloisters were inclined towards the Warden philosophy.
While nominally Warden, Clans Snow Raven and Steel Viper were in reality fence-straddlers. The Ravens would support Crusader motions that suited their goals, while the Vipers agreed with the Crusader aim of returning to the Inner Sphere and restoring the Star League under Clan leadership.
Clans Diamond Shark and Nova Cat, while pro-Crusader for much of their history, were motivated by benevolent intentions towards the Inner Sphere and so moved into the Warden camp after the Battle of Tukayyid. The Ghost Bears were also Crusaders until some time prior to the Great Refusal, when they officially announced their shift to the Warden stance.
While considered a Crusader Clan, some of Clan Fire Mandrill's Kindraa were supporters of the Warden philosophy. During the 3050s and early 3060s, the rank and file of Clan Hell's Horses were pro-Warden despite their Clan's staunch Crusader leadership. After 3065, the Horses would effectively shift to the Warden camp.
List of Warden Clans from c. 3050 to c. 3067
- Clan Cloud Cobra (Became a Bastion after the Wars of Reaving)
- Clan Coyote (Became a Bastion after the Wars of Reaving)
- Clan Diamond Shark (Crusader prior to Tukayyid)
- Clan Ghost Bear (Crusader until Great Refusal)
- Clan Goliath Scorpion
- Clan Hell's Horses (Crusader until Khan Malavai Fletcher's death in 3065)
- Clan Nova Cat (Crusader before Operation Bulldog)
- Clan Snow Raven (officially Warden, opportunistic supporter of Crusader policies)
- Clan Steel Viper (shared some Crusader goals)
- Clan Wolf (Crusader after Refusal War)
- Clan Wolf in Exile (extant after the Refusal War)
- Wolf Clan Sourcebook, p. 24
- Jade Falcon Sourcebook, p. 17
- The Clans: Warriors of Kerensky, p. 16
- The Clans: Warriors of Kerensky, p. 17
- Invading Clans, p. 52, "Wolfnet Archive File:07765-ER3-21/3/7"
- The Clans: Warriors of Kerensky, p. 20