Why blame Batman for the crimes commited by Harvey Dent?

I think that the question "why did a self-sacrificing hero (which the Batman surely is) take the blame instead of framing somebody else?" doesn't make sense.

To ask such a question properly, I think you'd have to make out a feasible alternative plan, taking into the account the current circumstances and the need to rig any evidence to fit Maroni and plenty of his men (no one would believe he did it alone) or whoever else.

Let us not forget that the place of Harvey's death was surrounded by the police force. They saw the Batman getting away, but - apart from him - only Jim Gordon and his family were there. So, how can the blame be put on anyone else (once we accept that the blame has to be put, which I find a bit weak)?

The death of Harvey Dent was going to be a huge blow to the city. Harvey had gotten rid of virtually all of corrupt crime in Gotham. Once word got out that he was dead, the public (I.E. the various newspapers, magazines and who knows who else) would naturally want to know the circumstances of his death. It would soon get out that Harvey had killed Maroni himself, as well as threatened Gordon and his kids. Such a bombshell would wind up destroying any hope that regular Gothamites would have had for the future. Not to mention that all the people Harvey would have locked up would naturally have wanted another day in court to argue that Harvey was not of sane mind when he prosecuted them. Most of the smaller criminals would still stay behind bars, but the larger ones would be able to use Harvey's turn as Two-Face as an almost literal 'get out of jail free card'. Gordon and Batman realised this. They needed someone to be an easy scapegoat in case any investigation got too close to the truth. Which is why Batman offered himself up. Being someone who many Gothamites either see as a figment or as someone who might be on the wrong side of the law, it'd be easy enough for Batman to be able to shoulder the blame. And as we saw at the beginning of The Dark Knight Rises, Bruce Wayne opted to simply stop being Batman for an extended period, making people think that he just simply disappeared.

It was possible to blame someone else but it wouldn't have worked for a few very real problems -

1. The lie wouldn't stand proper police investigation - When you think of it, the evidence against Harvey has to be pretty strong (in the real world). If we think of it as a real world incident, people must've seen Harvey out and about. His fingerprints, trace DNA evidence, real witnesses etc would have to be found in all murder locations. For example, when he killed the cop in the bar, it's pretty much impossible that no one saw him go all the way to the bar and then stand there as a bartender and what not. It's almost impossible in modern day to hide from a proper police investigation and rig things so that all fingerprints, DNA and various other types of clues/evidence/witnesses are completely gone. Gordon faced a very real problem because he could never be sure that he had cleared all of the evidence against Harvey. Even one scrap of evidence against Harvey would've made Dent's act impossible.

2. You can't blame anyone still alive - Anyone still alive (including Joker) would contest it in the court. And worse, if that person knew that it was Harvey, then he'd publicly blame Harvey resulting in more investigation and lengthy court proceedings which could, regardless of the results, negatively affect Harvey's immaculate reputation.

3. You can try to blame it on someone dead - But now (since it's real world), we risk a proper police investigation and run into #1 above. Further, if the person has any friends or family or anyone at all contesting, again we're looking at a lengthy police court case and police investigation that the lie may or may not stand. All it takes is just one reporter publishing "No, Harvey went crazy and did it, prove me wrong".

4. Dent Act - For the Dent act to pass, they really did need to hit the hammer while the iron (public opinion and Harvey's popularity) was hot. They didn't come out and explicitly say it but it makes sense because this act wouldn't have passed once the shock that the public was going through was over. If it took six months to an year, a new DA would've been appointed and things would've normalized and the intensity of the tragic events and Harvey and his sacrifice would've dulled in public mind.

5. The final crime scene leaves only Batman as the possible scapegoat - Imagine you're the first cop on the scene. You find a dead Harvey, Gordon & family and Batman (or worse Batman leaving the scene); what would you logically imagine transpired here? Accusing Gordon doesn't make sense and Harvey couldn't have done anything because he himself is dead. Now it's either some unknown criminal who managed to kill Harvey and leave the scene without any evidence whatsoever leaving both Batman and Gordon standing around...or the Batman did it.

6. Batman can't defend himself - In a real world investigation Batman would definitely be the biggest suspect. He is a vigilante carrying illegal weapons running amok in the city. He is the most logical suspect for who killed Harvey and potentially many other murders around the city and if an investigation ensues, he's possibly the only person who wouldn't come forward and subject himself to the investigation. No one knows that he has the thou-shalt-not-kill code, it's not a huge stretch to imagine that he's some sort of mentally deranged maniac with guns after real or imagined criminals. Finally, since he can't come out in the open and prove it wasn't him makes him all the more of a suspect.

tl;dr; In summary, the evidence against Harvey is already pretty strong and blaming someone else could risk a proper investigation that could potentially trace back to Harvey thus ruining everything. Batman is the obvious and strongest suspect and blaming him ensures that no investigation happens and no one questions Harvey. Basically, it was possible to find a different scapegoat but it was just too risky, the Batman route was the safest and the easiest.

It's really one of the main themes of "The Dark Knight." Like Hammer said, Batman and Commissioner Gordon both knew that this had to happen. You may have heard Commissioner Gordon say something like "He's not the hero they want, but he's the hero they need," referring to Harvey Dent.

In other words, the implication is that the average citizen would want Batman as their "hero." But for the sake of keeping order, the people need to put faith in someone. If they put faith in Batman or Gordon, then they can't cover up Two Face. If they don't cover up Two Face, then like the two above me have said, the city will corrupt. This was described by Hammer and Sego.

So the only remaining option is to let Harvey Dent still be their hero. Batman is selfless as their true hero, so he's willing to take the blame. But he and Gordon can't let people know that because that is no longer an option. Make sense?

Batman is a better option to take the blame than Gordon because Batman is such a strong character by comparison that he's able to take in all of that pain to help his city.

So, Batman is the "hero they want" in the sense that the people WANT to put faith in Batman. But Harvey's symbolism as a hero in the city will help keep order. It's who the people need to put faith in.

First of all, who were these five people Dent is said to have killed? We see him shoot Wurtz (he doesn't kill Ramirez) and Maroni's driver. At the end of Dark Knight only Gordon and Batman know what Dent has done, so technically they could say anything and still keep Dent's reputation clean. Also, it's not like Dent is a functioning district attorney, expected to show up at work on Monday, by the time he's in the hospital. Mayors can and do step-in to appoint new DAs (like police commissioners) if the old one is hurt or killed.

To me the plot hole is: Why would the public turn against Dent in the first place? Are we really suppose to believe that after the Joker's huge body count and highly-public attempts to take over Gotham that the public is going to look at their maimed-for-life ex-DA and decide to throw him under the bus?

Regardless of what the Mayor says earlier about "it's all on you" if something happens, there's clearly mitigating circumstances to show that the actions of Two-Face have no connection on the various legal decisions made by Harvey Dent prior to him going insane through grief, pain and losing half his face.

Batman had captured the Joker. So Harvey's death couldn't be blamed on him.The timeline wouldn't work. Others would talk that Harvey had turned bad. Batman was seen at the crime scene hobbling away as the police dogs went after him and he got on the Pod and took off.

I always understood it that by taking the blame on Batman, Bruce wanted to keep Harvey - the real hero - clean in the public eyes, and condone the Batman, because it was the existence of the Dark Knight which caused the Joker to appear. Commissioner Gordon said:

Because we have to chase him. Because he's the hero Gotham deserves, but not the one it needs right now, so we'll hunt him. Because he can take it because he's not a hero. He's a silent guardian, a watchful protector, a Dark Knight.

It was a time of change for Gotham, which Harvey Dent ("The White Knight" - opposite of the titular Dark Knight) started by ending Gotham's organized crime when he put Maroni on trial. And citizens of Gotham should continue to change for the better but that would be compromised if they found out that their heroic district attorney was corrupted by evil in the end, just like everyone else in Gotham. It was no longer needed for a dark, violent hero to stop crime. The courts in Gotham were ready to do it themselves, Gotham is rotten, it deserves, Batman, but it is time to change, Gotham no longer needs Batmans - it needs Harvey Dents.

Batman took the blame so that citizens of Gotham would stop admiring the violent and dark ways of Batman and start trusting the legal actions done in the daylight. No superheroes mean no supervillains. Harvey Dent remains good means less corruption and more legal actions in Gotham.

Unfortunately, the truth is that there is no good answer to this question, much as fans of the movie would like to imagine otherwise.

Which is not to say that there is no answer. There is an answer. It's just not a good one.

The answer is: Batman takes the fall for Harvey Dent's murders, because the director and/or screenwriter wanted him to.

Taking the blame for several murders doesn't make any sense on Batman's part. It can only make his attempts to fight crime in the future, much, much harder. Yes, he is willing to sacrifice himself for the good of the city, but there was no logical reason for Batman to sacrifice himself in this instance. They could easily have blamed the Joker or just let the crimes go unsolved. Yes, in a sense that would be immoral, they would be lying, etc. But they're still lying when they decide to blame it on Batman anyway. It's ridiculous.

Batman acts as he does because the film's creators wanted him to act that way. They wanted a more downbeat ending, no matter how implausible.

And that's the real answer.