When the delegation returned to Edinburgh with the Engagement, the Scots were bitterly divided on whether or not to accept its terms. Its supporters, who became known as the Engagers, argued that it offered the best chance the Scots would get of acceptance of the Covenant across the three kingdoms, and that rejecting it risked pushing Charles to accept the Heads of Proposals. It was opposed by those who believed that to send an army into England on behalf of the King would be to break the Solemn League and Covenant, and that it offered no guarantee of a lasting Presbyterian church in England; the Kirk went so far as to issue a declaration on 5 May 1648 that condemned the Engagement as a breach of God's law. After a protracted political struggle, the Engagers gained a majority in the Scottish Parliament, by which time war had again broken out in England between Royalists and Parliamentarians. The Scots sent an army under the command of the Duke of Hamilton into England to fight on behalf of the King in July, but it was heavily defeated at Preston by a force led by Oliver Cromwell. The rout of the Engager army led to further political upheaval in Scotland, and the faction opposed to the Engagement was able to regain control of the government, with the assistance of a group of English parliamentary cavalry led by Cromwell.