[Please understand that the question was revised because Enotes editors do not compose essays; we are happy to advise students, however.]
With Richard II, the question of the divine right of kings vs. political/judicial authority arises. That is, is the measure of a ruler's right to power the justice of his claim, or is it the quality of his actions at the helm of state? King Richard certainly has the legal right to the throne; however,he loses the support of the people when he acts illegally. For. he is suspect in the death of Gloucester; moreover, he violates the law of inheritance when he confiscates Gaunt's estate rather than allowing Bolingbroke, his son to receive it along with the father's money. As a result of these illegal actions, Richard loses the support of his kingdom while Bolingbroke stirs the hearts of the citizens who sympathetically perceive him as a victim of much misfortune, having lost his inheritance and having been unjustly exiled, as well.
In the climax of Act III, Bolingbroke has invaded England, seeking redress from Richard II to "lay my claim/To my inheritance of free descent" (2.3.135-136). Clearly, he acts in a kingly manner when he orders the deaths of Richard's advisers, but he seems ruthless in this action, and in his forcing of Richard's abdication. In response, Richard tells Bolingbroke
...but still my griefs are mine.
You may my glories and my state depose,
But not my griefs; still am I king of those. (4.1.185-187)
In King Lear the divisiveness of the family again secures tragedy as Lear abdicates the throne and divides his kingdom; his error is in linking this division to a show of affection. Too long accustomed to the flattery of his court, Lear has figuratively blinded himself to truth. But, his youngest and unmarried daughter Cornelia cannot cajole him as the others do. Having based his kingdom upon a false custom, Lear even exiles his devoted courtier, the Earl of Kent, who defends Cornelia.
In the end, while the wicked are punished, unfortunately, so are the good. The Earl of Gloucester, a parallel to Lear, who favors his illegitimate son over his legitimate one, suffers the loss of his eyes at the hands of the cruel Cornwell. This blindness is symbolic of both his and Lear's sightlessness. Expressing his blindness to the intentions of his illegimate son, Gloucester declares significantly,
I have no way, and therefore want no eyes;
I stumbled when I saw" (4.1.18-19).
Perhaps common to both plays is the concept of noblesse oblige,the suggestion that "noble ancestry constrains to honorable behavior; privilege entails to responsibility" [Oxford English Dictionary]. Both King Richard II and King Lear either ignore or evade their responsibilities, and, in so doing, they disrupt the Elizabethan Chain of Being and bring upon themselves retaliation or corruption or confusion; in short, they effect their own tragic ends.