First, whether I like their actions or not the majority of their actions publicly appear to be through legal channels (at least by US law, we could argue about international law)
However, you have to separate "mistakes" that is, policy judgments that you think are wrong with things that are illegal.
I think the war itself was constitutional in that they got an AUMF and that's all we seem to require these days rather than actual declarations of war like we should do, but I think it was wrongly fought.
Also, Cheney and any residual ties and influences with Halliburton with regards to the wars need to be examined for specific illegal conducts.
But all of that, honestly? That doesn't compare to targeting civilians repeatedly on 9/11 or the Embassy bombings, or the FIRST WTC attack in '93, etc etc etc. I really don't like "defending" Bush and Cheney but you really need a little bit of perspective. Just like I don't agree with many of Obama's POLICIES none of that has anything to do with anything personal.
Who wrote the AUMF? It's difficult to judge someone under the law when they write the laws. The AUMF was passed on September 14, 2011, three days after the 9/11 attacks. It gave the President an unprecedented amount of autonomy in regards to war. So yes, it was legal for them to start major conflicts in the Middle East, bearing in mind that legality was established a mere three weeks before war against Afghanistan was declared, and probably for that very reason. It wasn't a coincidence.
"However, you have to separate "mistakes" that is, policy judgments that you think are wrong with things that are illegal."
Again, the legality of his actions means nothing to me, considering how easily he facilitated legality.
Cheney's ties to Halliburton are indisputable. Another thing that is indisputable is that Halliburton was the only company afforded the opportunity to bid for an energy exploration contract in the run-up to the war. You are being naive if this strikes you as mere coincidence. It's a typical "you scratch my back, I scratch yours" situation. The strong relationship between politicians and the corporate sector, and the ease with which members of either sector can transfer seamlessly into the other is exemplary of corruption.
"But all of that, honestly? That doesn't compare to targeting civilians repeatedly on 9/11 or the Embassy bombings, or the FIRST WTC attack in '93, etc etc etc."
Put yourself in the perspective of a civilian living in Afghanistan during the invasion. When your world is collapsing before you and sheet rock from exploding buildings is raining down upon you and your loved ones, do you stop to think about the people doing these things? Do you say to yourself, "these aren't terrorists, they're American soldiers?"
As I said before, human beings are pliable. You give a man a title, you give his men uniforms, and suddenly it's okay. There's a bureaucratic banality to it. It's expected, it's normal. You've heard their names dozens of times on the news. So there's that positive fluency in your mind. And then suddenly the news chimes out the name of some guy you've never heard of before, whose existence meant nothing to you 2 minutes ago, and you don't know anything about him, the sound of his voice, what he does in his spare time, and of course, you don't want to compare someone you have a fairly good idea about with some foreigner who's just carried out the deaths of 3,500 people.
Dick Cheney is to many people what Osama bin Laden was to us.