Wars of the Three Kingdoms: There could have been a negotiated settlement at the end of the first civil war.

The main point raised against the Royalists by the Parliamentarians, as it the case in almost all rebellions, was that “the venom of those Traiterous counsellors about his majesty”[[England and Wales. Parliament. A declaration and resolution of the Lords and Commons assembled in Parliament, London, 1642, EEBO, E.112[6], p3]] were those at fault. Parliament also blamed this misguided council for the immediate start of the war “Since which time by their perpicious Councells, they have caused his Majestie to ingage himselfe in a Warre against Hull”[[England and Wales. Parliament. The Parliaments protestation: Or The resolution of the Lords, and Commons, to maintaine the iust priuiledge of Parliament, London, 1642, EEBO, E.109[6], p3]] However these allegations against counsellors show the true reasons for parliaments fight against the King:

[quote=parliament]“Who having for many yeers together carried a wicked designe to alter Religion, and to introduce Popery, Superstition, and Ignorance (the ready way to an Arbitrary and Tyrannical Government)”[[ England and Wales. Parliament. A declaration and resolution of the Lords and Commons assembled in Parliament, London, 1642, EEBO, E.112[6], p3-4]][/quote]

Thus Parliament was fighting to prevent the King accruing absolute authority as was occurring elsewhere in Europe.

Parliaments aims of preventing an absolutist King and replacing any misguided counsellors are brought about as soon as the King is in their hands. The King on the other hand is presented with a fait accompli; parliament has control of the army and any counsel to the King. At the end of the war it would seem that the King should be willing to accept a peace treaty that is based upon parliaments war aims, after all he has lost nothing since just before the war.

King Charles however was fighting to regain privileges that he believed parliament had taken from him: 
 
[quote=Charles I]“And having by that declaration (as far as in the lies) devested Us of that pre-eminence and authoritie, which God, the Law, the Custome and Consent of this Nation has placed in Us, and assumed it to themselves”[[England and Wales. Sovereign (1625-1649 : Charles I), His Majesties declaration to all his loving subjects, occasioned by a false and scandalous imputation laid upon His Majesty of an intention of raising or leavying war against his Parliament, and of having raised force to that end, London, 1642, EEBO, p3]][/quote] 
 
Particularly the Kings privileges in relation to his command of any army 
 
[quote=Charles I]“That they should likewise with expedition put forth the fruits of that supream power, for the violating and suppressing that power they despised (an effect of which resolution their wilde Declaration against Our Proclamation concerning the pretended Ordinance for the Militia, and punishing of the proclaimers appears to be) yet we must confess, in there last attempt… they have out-done what We conceive was their present Intention; And whosoever hears of Propositions and Orders for the bringing in of Money or Plate to maintain Horse, Horse-men and Arms for the preservation of the public Peace, or for the defence of the King, and both Houses of Parliament… and (at least) the King himself to be consulted with, and privie to these Propositions”[[ibid, p3]][/quote] 
 
Charles is complaining against the hypocrisy of parliament for attempting to raise an army while denying his sovereign right to raise and lead any army in defence of the Kingdom.