In the most base sense Hayden fits the role perfectly with his deep voice and simply his size of the man that this would be guy who would not mind intiating such a plan on his own personal authority. Hayden makes Ripper the obvious example of military might and the thinking of a man who believes himself to be in complete command of the situation. In the most serious sort of way Hayden fulfills the purpose of General Ripper, by being a man who is clearly determined in his plan no matter what the consequences will be in the end. Of course this role and Hayden's performance has much more to offer than simply being a determined military general, as the true nature of this role is not dramatic but in actuality it is comedic.
Hayden is brilliant in regard to making this a hilarious performance. The great part about Hayden's performance is he doesn't play it straight nor does he seem like he is playing it as funny either. Hayden does so much within the structure of Ripper it is amazing. As Ripper he is always chomping hard on his large cigar throughout his performance, and he has a most crazy eyed look on his face. There is something so intense about his look that it is both hilarious yet as well works in portraying the insanity of Ripper. This goes for almost everything he does as Hayden is so extreme about it that he makes what he does amusing yet he is strangely believable at just being a purely crazed war hungry General as well.
The best part of Hayden's performance though his his bizarre yet so perfect chemistry with Peter Sellers as Ripper's sane second in command Lionel Mandrake. Although Mandrake the whole time is trying to stop Ripper, Ripper never figures this out revealing much of his plan to Mandrake. Hayden is rather warm and almost fatherly toward Mandrake throughout the event making a real camaraderie there even though Mandrake is trying to undermine him the entire time. Hayden having Ripper seem so comfortable rather than hostile when talking to Mandrake makes the situation all the funnier as Mandrake tries to find something out while Ripper is in a world of his own.
The reason for Ripper's plan is the most ridiculous part of his character as he reveals that he believes the communists are after his precious bodily fluids because he apparently knows nothing about the way the human body works. Hayden brings so much conviction to this lunacy with his stone cold delivery that he makes the scene as memorable as it is, and makes it seem perfect sense to General Ripper anyway. Although I am sure that is many a fan's favorite scene for Ripper, my personal favorite is when Ripper asks Mandrake about torture. Hayden's performance is extremely funny as he keeps that psychotic look, but within that look you can see him basically wimping out at the idea of any physical torture.
Hayden proves himself far more capable actor than one who is just good at fulfilling a certain physical type of character with his performance in Dr. Strangelove. It is quite true that Hayden successfully fulfills General Ripper in the basic description of an imposing General, but more than that he turns his depiction of a General out of his gourd into a comedic gold. Hayden gives a great performance that pulls off a most interesting trick which is to not pigeonhole himself as really playing it exactly one way or another. Sterling Hayden by taking this most unique path gives a completely fitting portrait of a man who very much has created his own form of reality within his deranged mind.