Charles as king, could do this under what was known as Royal Prerogative, the divine right to rule, but by the middle of the century he was wading into trouble, many people regarding him as insensitive.
The West Country, the home of my maternal ancestors, were notable Royalist, suffered at this time, the town of Barnstaple for instance, changed from Royalist to Parliamentarians and back again no fewer that four times.
The year 1649 saw a great change in the governance of England, in the January of that year the trial of Charles I had begun. The country had seen the estimated deaths from the civil wars as 84,830 killed with another 100,000 dying from war related diseases, and therefore the king was held
"guilty of all the treasons, murders, rapes, burnings, spoils, desolations, damages and mischiefs to this nation”
Charles was declared guilty on Saturday 27 January 1649 and sentenced to death and was executed by beheading on the 30th January 1649.