War was probably inevitable even before the shooting started on Lexington Green that day. The fact that the colonists, as shown by their rapid response during the British retreat from Concord, were so well prepared for any attempt by the British to seize their stocks of weapons is evidence enough that armed conflict would have broken out sooner or later. Once this had happened, however, the question remains as to whether or not the conflict would necessarily have escalated into full-scale warfare as it did.
In my view, "total" war is never absolutely inevitable. One of the remarkable things about the War of Independence was the degree of sympathy for the colonists that existed in Britain, especially, of course, in the Whig Party. Edmund Burke and others in the Parliamentary opposition believed the Americans' rights as Englishmen had been violated. Burke decried the steps the government had taken in closing the port of Boston and essentially enacting military rule there. However, the king and his administration were absolutely committed to quashing any sort of defiance on the part of the colonies. If conciliatory measures had been carried out by the king, it was still possible the conflict could have been defused after the events on April 19. But he and his ministers had no such intention. Each thing that happened from this point on inflamed both sides all the more. The greater the violence and killing, the less likely either side would back down. Especially after the Battle of Bunker (Breeds) Hill two months later, in which both sides took a shocking number of casualties, the likelihood of any peace agreement soon was nil.