what impression would you form of a state where the king was 'just and placid' ?

A state that is governed by a just and placid king would be an ideal state where the ruler works with a sane head on his shoulder. However, the kingdom that is referred to in the poem is not an ideal state and the ruler takes decisions without thinking them through. A sense of delivering justice and placidity though ideal qualities in a ruler should not be the only ones,he should also have tact,common sense and a certain modicum of intelligence to deal with matters of the state.