If the waging of war was an expected aspect of governance under the Norman and Angevin kings, says Matthew Strickland, ‘then much of this warfare was directed against rebellious vassals, often themselves leagued with the external enemies of the Anglo-Norman regnum’. The nine weeks spent by King John in Ireland in 1210, during which he expelled the de Lacys from Ulster and Meath, remains a key set-piece in the relationship between crown and colony in the medieval period. Of the countless treatments of John's summer campaign, perhaps none has been more insightful into the king's motivations than the near-contemporary ‘Barnwell’ chronicle, which states the king's foremost concern to have been the suppression and punishment of the earl of Ulster:

Having been elevated to comital rank by King John, the earl of Ulster's involvement in sedition appears on first glance to be ungrateful in the extreme. As Bothwell notes, ‘one of the best ways to incense a king and bring about one's own quick, and often painful, demise was not only to betray the monarch's sacred trust – his realm – but to do so after the king had been foolish enough to show great favour’. It was the withdrawal of royal esteem, however, which seems to have caused Hugh to bite the hand which had so recently nourished him with an earldom. William Marshal's swift restoration into the king's graces in 1205 removed the need for a counterbalance to his power in Ireland. The subsequent exclusion of Hugh de Lacy's comital title in royal correspondence to the Irish colony implies that the king was actively ignoring or suppressing de Lacy's status as comes Ultonie.

It is the slight to his comital dignity which best explains Hugh's enthusiastic resistance to the royal faction during the baronial war of 1207–08, as well as his cultivation of links to opponents of the English crown outside Ireland. By 1209, with his kingdom already under interdict, King John found himself beset by conspirators, rebellious barons and hostile neighbours.