This is a guy who managed to go from House Majority Whip to President of the United States within, probably, two years, and he didn't even have to get elected. Is Frank a morally abhorrent, unethical, murderous, conniving *******? Hell yes he is. Is he also a damn good politician? I'd say so. So, while I was joking, now, I'm not so sure. That kind of devotion to seeing things through makes me very curious as to what sort of White House he'll be running in Season 3. We've seen just what he's capable of, politically, with his education reform and energy bills, and that's when he's at half concentration (the majority of his mind was seemingly busy plotting his Machiavellian master plans). For the most part, the guy managed to unite the Congress, so, imagine what he'd be capable of with total executive authority.
No doubt, what he did to Zoe Barnes and Peter Russo was horrible, but I don't think he's bloodthirsty. It's cliche, but the first thing that comes to mind is "nothing personal, just business." They stood in the way of progress, so, he removed them from the equation. Is that a totally sociopathic thing to say? Absolutely, but take a look at our nation's history. Our Government slaughtered Native Americans for the same (possibly worse) reasons. I'm still not saying it's right, but I'm just saying that, even though he killed them, it's not like Dexter's in the White House, and, really, the murders aren't really relevant to the situation, as I was thinking objectively from the stance of someone in that universe who didn't know what he did. Judging Frank Underwood purely as a Politician; I probably would vote for him.