At first Oliver tried to save Charles' life. After he arrived in London, however, he seemed to sense that the providence of God had specially arranged these events and he was soon arguing for Charles' execution, even to the point of overseeing the signature of the death warrant. By 1653, however, the revolution was over and the nation was tired of war and its high costs. Cromwell not only had defeated the Crown, he was also at odds with his former comrades in arms, many of whom were executed. In his inaugural oath he swore to protect freedom, property rights and to advance the gospel of Christ.
Governors are typically more conservative than campaigners.
Soon Cromwell was discovering that the national unity obtained during war, doesn't often last in peace. The simple matters of civil administration and justice had to be attended to. So, ironically, he turned increasingly to the landed nobility for help in ruling England. Once in power, it is also alleged, Cromwell even made use of an astrologer to predict the future. The first parliament under Oliver's protectorate closed in failure.