I want to say YES, but I have no idea how to do it. First you gotta catch them, then you gotta prove it. As an attorney, I’m sure you know the drill… You have to prove a “crime” (figuratively speaking) before you can punish a person. And then, just how do you punish?
Back to the topic of the OP, stronger libel laws might help in some cases, but not all. For starters, truth is a defense against charges of libel, and I think that’s a baby we don’t want to throw out with the bathwater. But it’s still possible to use dirty smears against someone that are entirely true: For instance, it’s absolutely true that John McCain has a brown daughter (Bridget, adopted from Bangladesh). But someone could spread the rumor (via push-polls, forwarded e-mails, whatever) along the lines of “Did you know that McCain has a brown daughter? I wonder how that might have happened?”, with the intent to discredit him (implying, perhaps, but not actually stating that he had an affair with a black woman). Do we want to prosecute the rumor-mongers for saying something that is, after all, true (even if sleazy and misleading)?
For that matter, not all dirty tricks work through defamation of character in the first place. Consider, for instance, the old tactic of announcing “Republicans vote on Tuesday, and Democrats vote on Wednesday” (or equivalently, distributing flyers in presumed-Democratic neighborhoods that the voting day is Wednesday). I think everyone agrees that that’s a dirty trick, but stronger libel laws wouldn’t do a thing against it. Of course, there, I suspect that there are already laws against it; the difficulty lies in determining who’s behind it.
Getting rid of public figures doctrine isn’t the solution. Even if you could do it in a way that wouldn’t substantially chill political speech – and I don’t see how you could – it wouldn’t do any good.
First, almost no dirty tricks are provably false, cause quantifiable damage, and are attributable to an identified source. Most dirty tricks don’t involve verifiable statements of fact, either because the accusation is deliberately vague, the fact is unfalsifiable, it is pure opinion, or some combination (see, e.g., death panels). And even for that subset of dirty tricks which include falsifiable statements of fact, they almost never do any provable damage, especially when the source is known. So the threat of nominal damages from a lawsuit isn’t very threatening at all.
Second, as has already been pointed out, giving the issue more attention (by instigating a lawsuit over it) just makes the situation worse. There’s no such thing as successful factual debunking over the short-term. Consequently, savvy politicians wouldn’t pursue that strategy until it didn’t matter to the political result anymore anyway.
The reason Rove did not know about it is because it never happened. There was an automated call attacking McCain for saying mean things about Bush and an email smear about McCain fathering his adopted daughter that was started by someone who had no affiliation with the Bush campaign. The two were conflated by a twelve year old boy who asked McCain about them at a campaign stop. No one has ever come forward with a credible claim that a push poll claiming McCain fathered his adopted daughter ever happened. Since about 20% of automated telephone calls are recorded on answering machines, if such a call existed it would have been very easy to prove.
I thought in libel per se no damages need to be shown? Am I missing something?
Without a Department of Truthiness (or similar though less awesomely-named organization), I don’t see who is going to define a dirty trick.
ETA: That is to say, I think Rush Limbaugh uses dirty tricks on a daily basis, but Shodan presumably does not. Who is to say who’s right?
The thing is, and this is an interesting issue, is that without knowing the persons character you can’t know if what they claim they want to do is true. On a related note, if a pol is a coke head for example, it opens him or her up to all kinds of blackmail and other issues. This goes for cheating, extra-marital children, etc.
The bigger problem, I think, is that politics has become a game to the politicians and we allow it. I believe that any politician caught in a lie or with a provable ethical issue* needs to be have their asses kicked right out no matter what side of the aisle they are on.
Of course, that will never happen because presently everyone is more concerned with pushing their particular agenda even when the methods used to push that agenda are dishonest.
Somehow we let politicians get away with stuff that we would never let our friends or family do. Well, most of us anyway 
We should expect our politicians to have high ethical standards yet we generally don’t care as long as they say the right things. The problem isn’t the pols, it is that we let them get away with this shit.
We know, and expect, politicians to lie. We know and expect that they will change their positions on policy depending on how the polls are going. We know, and expect, that many of their political positions are held so they can get elected, not because of any deep seated belief. We know this and we let it happen.
We dislike the dirty tricks then vote for the politician who used them anyway because he or she agree with the positions we believe in. Or say they do anyway.
The dirty tricks will stay as long as we let them get away with it.
Slee
*The ethical issues surrounding sex scandals are complicated. However, if a pol can’t keep it in his pants when knows he should, why should we trust him with other things? It is pretty damned easy to not have an affair. And it is pretty well known that those who do have affairs often get caught. This points to very bad judgement on the pols behalf.
Clearly my country needs me to volunteer.