The writer and critic Samuel Johnson wrote that Paradise Lost shows off "[Milton's] peculiar power to astonish" and that "[Milton] seems to have been well acquainted with his own genius, and to know what it was that Nature had bestowed upon him more bountifully than upon others: the power of displaying the vast, illuminating the splendid, enforcing the awful, darkening the gloomy, and aggravating the dreadful."
Regarding the war in the poem between Heaven and Hell, the Milton scholar John Leonard writes:
Paradise Lost is, among other things, a poem about civil war. Satan raises 'impious war in Heav'n' (i 43) by leading a third of the angels in revolt against God. The term 'impious war' implies that civil war is impious. But Milton applauded the English people for having the courage to depose and execute King Charles I. In his poem, however, he takes the side of 'Heav'n's awful Monarch' (iv 960). Critics have long wrestled with the question of why an antimonarchist and defender of regicide should have chosen a subject that obliged him to defend monarchical authority
However, the editors at the Poetry Foundation argue that Milton's criticism of the English monarchy was being directed specifically at the Stuart monarchy and not at the monarchy system in general.
In a similar vein, C.S. Lewis argued that there was no contradiction in Milton's position in the poem since, from Lewis' point of view, "Milton believed that God was his 'natural superior' and that Charles Stuart was not." Others, like literary critic William Empson argued that "Milton deserves credit for making God wicked, since the God of Christianity is 'a wicked God.'" Leonard places Empson's interpretation "in the [Romantic interpretive] tradition of Blake and Shelley." As the poet William Blake famously wrote, "The reason Milton wrote in fetters when he wrote of Angels & God, and at liberty when of Devils & Hell, is because he was a true Poet and of the Devil's party without knowing it." And this quotation succinctly represents the way in which the 18th- and 19th-century English Romantic poets viewed Milton. However, Empson's view is more complex. Leonard points out that "Empson never denies that Satan's plan is wicked. What he does deny is that God is innocent of its wickedness: 'Milton steadily drives home that the inmost counsel of God was the Fortunate Fall of man; however wicked Satan's plan may be, it is God's plan too [since God in Paradise Lost is depicted as being both omniscient and omnipotent].'"
Although Leonard calls Empson's view "a powerful argument," he notes that this interpretation was challenged by Dennis Danielson in his book Milton's Good God (1982).