Henry V: Theme Analysis

Is Henry V a play that glorifies war? Or is it the reverse, a play that shows the ugliness and inhumanity of war?
After his brilliant victory against the French at Agincourt, the historical Henry V has long been one of the most revered of English kings.  And for three centuries, everyone thought that Shakespeare's Henry V was a portrait of the ideal king who embodied the four cardinal virtues of justice, fortitude, temperance, and prudence. This is how Henry is portrayed in Shakespeare's sources, the historians Hall and Holinshed.  In the play, before we even see Henry, we hear the bishops praising him to the skies, saying how complete and miraculous has been his transformation from his days as the wild Prince Hal. He is later described as "the mirror of all Christian kings" (Act 2, line 6, Chorus), and is presented as an epic hero, not unlike Aeneas in Virgil's Aeneid,  who gives all the praise for his success to God.  Henry appears to be the perfect warrior, the perfect man.
But not everyone sees it like this. The first critic to see the play differently was essayist William Hazlitt in the early 19th century, who described Henry as an "amiable monster."  Then in 1919, just after the horrors of World War I had shocked all of Europe, Gerald Gould claimed the play was ironic, and that Shakespeare "must have felt revolted by Henry's brutal and degrading militarism."  Another critic, Mark van Doren, derided Henry as "a hearty undergraduate with enormous initials on his chest."  Although Laurence Olivier's famous film version of the play, in 1944, was wholly in heroic mode, 20th century views of Henry have tended toward the  skeptical and anti-heroic.  This of course may say as much about our own times as the play itself, but the question is valid: What sort of a man was Shakespeare's Henry V?
The case against Henry rests on several points. First, his dubious reasons for going to war.  The vital question is the validity of Henry's claim to the throne of France, which is explained at tedious length by the clerics in Act 1 scene 2. The French unearth what is called the Salic Law, which says that no monarch can inherit the throne through descent from the female line.  But this is exactly Henry's position.  He was descended from Philip IV of France through the female line:  Philip's daughter, Isabella, married Edward II of England, and produced Edward III, who unsuccessfully made a claim for the French throne.  Since Henry V  was Edward III's great-grandson, he renewed the claim to the throne.
To modern eyes, this is a bad excuse for a war. That a king could invade another country and justify it by some obscure trick of genealogy strikes us as indefensible. To be fair, however, we might remember that people in medieval times thought differently than we do. Regarding Henry's claim to the French throne, for example, Peter Saccio in his book, Shakespeare's English Kings, points out that "The inheritance of property by the correct bloodlines was an extremely serious matter in the Middle Ages and long after.  It was an elementary premise undergirding the whole social organization."  Understood in that light, Henry's claim may not seem so outrageous.
Other matters raised against Henry include his  bloodthirsty speech at the siege of Harfleur, and his order to kill the French prisoners, which is often regarded as morally unjustifiable. The latter charge has proved hard for Henry's defenders to refute. It is often cut  in performance, and both Olivier, in his 1944 film, and Kenneth Branagh, in his 1989 movie version, omitted it.      
Henry has also been heavily  criticized for the heartless way  he  rejects his pal and drinking companion, the old rogue Falstaff, and allows another old tavern chum, Bardolph, to be hanged. Against this view, it might be argued that the King has responsibilities to his office and his country that necessarily transcend merely personal  matters. On becoming King,  he must follow his duty, not his personal feelings.
Another charge against Henry has been that he takes the cynical advice his father offers him in Henry IV:  If you want to keep the peace at home, stir up a foreign war, which means that all your nobles have to be out there on the battlefield with you, rather than at home plotting against you!  
The modern variant of this time-honored political strategy has become known as the "wag the dog" scenario, after Barry Levinson's 1998 movie of that title in which an American president starts a fake war in Albania to divert attention from a domestic scandal. 
That's quite a rap sheet for the "ideal king," however brilliant a leader he may have been. However, many of the points raised against him are debatable, and we must be wary of judging historical characters by the standards of today. This can often give a false picture. We have to make up our own minds about Henry, bearing in mind that we can't see this play through Elizabethan eyes.  The last century saw two world wars, and America suffered through the disillusionments of Vietnam and Watergate:  we no longer view war as a glorious or heroic enterprise, often have little trust in our leaders, and condemn wars of aggression.  So our response to the play is conditioned by the times in which we live.