Power or Ethics?
Should a society allow the most powerful to make the rules, or should it govern itself according to ethical principles? According to Swift's "A Modest Proposal," the British government used its power rather than ethics to create its rules. The rich profited while the poor starved; the powerful accumulated more and more, while the weak were left with nothing.
In Lilliput, Gulliver has unlimited power but places himself in the service of the monarch; he drags the navy of rival Blefuscu out to sea. However, when he urinates in the queen's chamber to put out a palace fire, he is accused of treason -- a sign of how contrary to human nature it can seem to subjugate power to ethics at times.
The Laputans might be the closest analog to the relationship between England and Ireland, in Swift's opinion -- to squelch rebellion on the lower land of Balnibarbi, Laputa would threaten to hover right over the land, blocking sun and rain, or even crushing buildings and people on the land below.
Leaders who claim the high moral ground also have a hard time proving their claims. Look at the egg dispute between Lilliput and Blefuscu -- this centers on a matter of religious interpretation that has driven the nations apart.
And so what is the answer? It's easier to prove superiority based on power, but it's also easier to justify overthrowing that sort of power. On the other hand, it's harder to prove ethical superiority, but it's harder to justify rebelling against it. Small wonder, then, that so many monarchs in the age of Swift tried to rely on both.