The causes which moved the Convention of Estates at this time to take such an immediate and active interest in the civil war of England, are detailed in our historians, but may be here shortly recapitulated. They had indeed no new injury or aggression to complain of at the hand of the King, and the peace which had been made between Charles and his subjects of Scotland had been carefully observed; but the Scottish rulers were well aware that this peace had been extorted from the King, as well by the influence of the parliamentary party in England, as by the terror of their own arms. It is true, King Charles had since then visited the capital of his ancient kingdom, had assented to the new organization of the church, and had distributed honours and rewards among the leaders of the party which had shown themselves most hostile to his interests; but it was suspected that distinctions so unwillingly conferred would be resumed as soon as opportunity offered. The low state of the English Parliament was seen in Scotland with deep apprehension; and it was concluded, that should Charles triumph by force of arms against his insurgent subjects of England, he would not be long in exacting from the Scotch the vengeance which he might suppose due to those who had set the example of taking up arms against him. Such was the policy of the measure which dictated the sending the auxiliary army into England; and it was avowed in a manifesto explanatory of their reasons for giving this timely and important aid to the English Parliament. The English Parliament, they said, had been already friendly to them, and might be so again; whereas the King, although he had so lately established religion among them according to their desires, had given them no ground to confide in his royal declaration, seeing they had found his promises and actions inconsistent with each other. "Our conscience," they concluded, "and God, who is greater than our conscience, beareth us record, that we aim altogether at the glory of God, peace of both nations, and honour of the King, in suppressing and punishing in a legal way, those who are the troublers of Israel, the firebrands of hell, the Korahs, the Balaams, the Doegs, the Rabshakehs, the Hamans, the Tobiahs, the Sanballats of our time, which done, we are satisfied. Neither have we begun to use a military expedition to England as a mean for compassing those our pious ends, until all other means which we could think upon have failed us: and this alone is left to us, ULTIMUM ET UNICUM REMEDIUM, the last and only remedy."
Leaving it to casuists to determine whether one contracting party is justified in breaking a solemn treaty, upon the suspicion that, in certain future contingencies, it might be infringed by the other, we shall proceed to mention two other circumstances that had at least equal influence with the Scottish rulers and nation, with any doubts which they entertained of the King's good faith.
The first of these was the nature and condition of their army; headed by a poor and discontented nobility, under whom it was officered chiefly by Scottish soldiers of fortune, who had served in the German wars until they had lost almost all distinction of political principle, and even of country, in the adoption of the mercenary faith, that a soldier's principal duty was fidelity to the state or sovereign from whom he received his pay, without respect either to the justice of the quarrel, or to their own connexion with either of the contending parties. To men of this stamp, Grotius applies the severe character—NULLUM VITAE GENUS ET IMPROBIUS, QUAM EORUM, QUI SINE CAUSAE RESPECTU MERCEDE CONDUCTI, MILITANT. To these mercenary soldiers, as well as to the needy gentry with whom they were mixed in command, and who easily imbibed the same opinions, the success of the late short invasion of England in 1641 was a sufficient reason for renewing so profitable an experiment. The good pay and free quarters of England had made a feeling impression upon the recollection of these military adventurers, and the prospect of again levying eight hundred and fifty pounds a-day, came in place of all arguments, whether of state or of morality.
Another cause inflamed the minds of the nation at large, no less than the tempting prospect of the wealth of England animated the soldiery. So much had been written and said on either side concerning the form of church government, that it had become a matter of infinitely more consequence in the eyes of the multitude than the doctrines of that gospel which both churches had embraced. The Prelatists and Presbyterians of the more violent kind became as illiberal as the Papists, and would scarcely allow the possibility of salvation beyond the pale of their respective churches. It was in vain remarked to these zealots, that had the Author of our holy religion considered any peculiar form of church government as essential to salvation, it would have been revealed with the same precision as under the Old Testament dispensation. Both parties continued as violent as if they could have pleaded the distinct commands of Heaven to justify their intolerance, Laud, in the days of his domination, had fired the train, by attempting to impose upon the Scottish people church ceremonies foreign to their habits and opinions. The success with which this had been resisted, and the Presbyterian model substituted in its place, had endeared the latter to the nation, as the cause in which they had triumphed. The Solemn League and Covenant, adopted with such zeal by the greater part of the kingdom, and by them forced, at the sword's point, upon the others, bore in its bosom, as its principal object, the establishing the doctrine and discipline of the Presbyterian church, and the putting down all error and heresy; and having attained for their own country an establishment of this golden candlestick, the Scots became liberally and fraternally anxious to erect the same in England. This they conceived might be easily attained by lending to the Parliament the effectual assistance of the Scottish forces. The Presbyterians, a numerous and powerful party in the English Parliament, had hitherto taken the lead in opposition to the King; while the Independents and other sectaries, who afterwards, under Cromwell, resumed the power of the sword, and overset the Presbyterian model both in Scotland and England, were as yet contented to lurk under the shelter of the wealthier and more powerful party. The prospect of bringing to a uniformity the kingdoms of England and Scotland in discipline and worship, seemed therefore as fair as it was desirable.
The celebrated Sir Henry Vane, one of the commissioners who negotiated the alliance betwixt England and Scotland, saw the influence which this bait had upon the spirits of those with whom he dealt; and although himself a violent Independent, he contrived at once to gratify and to elude the eager desires of the Presbyterians, by qualifying the obligation to reform the Church of England, as a change to be executed "according to the word of God, and the best reformed churches." Deceived by their own eagerness, themselves entertaining no doubts on the JUS DIVINUM of their own ecclesiastical establishments, and not holding it possible such doubts could be adopted by others, the Convention of Estates and the Kirk of Scotland conceived, that such expressions necessarily inferred the establishment of Presbytery; nor were they undeceived, until, when their help was no longer needful, the sectaries gave them to understand, that the phrase might be as well applied to Independency, or any other mode of worship, which those who were at the head of affairs at the time might consider as agreeable "to the word of God, and the practice of the reformed churches." Neither were the outwitted Scottish less astonished to find, that the designs of the English sectaries struck against the monarchial constitution of Britain, it having been their intention to reduce the power of the King, but by no means to abrogate the office. They fared, however, in this respect, like rash physicians, who commence by over-physicking a patient, until he is reduced to a state of weakness, from which cordials are afterwards unable to recover him.
But these events were still in the womb of futurity. As yet the Scottish Parliament held their engagement with England consistent with justice, prudence, and piety, and their military undertaking seemed to succeed to their very wish. The junction of the Scottish army with those of Fairfax and Manchester, enabled the Parliamentary forces to besiege York, and to fight the desperate action of Long-Marston Moor, in which Prince Rupert and the Marquis of Newcastle were defeated. The Scottish auxiliaries, indeed, had less of the glory of this victory than their countrymen could desire. David Leslie, with their cavalry, fought bravely, and to them, as well as to Cromwell's brigade of Independents, the honour of the day belonged; but the old Earl of Leven, the covenanting general, was driven out of the field by the impetuous charge of Prince Rupert, and was thirty miles distant, in full flight towards Scotland, when he was overtaken by the news that his party had gained a complete victory.
The absence of these auxiliary troops, upon this crusade for the establishment of Presbyterianism in England, had considerably diminished the power of the Convention of Estates in Scotland,