I'm a sucker for a surprise ending, the big "oh my god" plot twist that movie critics sneer at and call a "gimmick." Warning: I am about to spoil such an event in A Beautiful Mind. You've been warned.
The movie is a biography of John Nash, who for most of the audience is "some smart guy you've never heard of." The story starts with John in college, working on some super-smart research project on a cushy scholarship. We learn that he's crazy-smart, but also kinda eccentric. He has awkward conversations with girls, follows pigeons around campus, knocks over board games when he loses, standard Hollywood-smart-nerd behavior.
So he makes friends with his roommate, awkwardly courts a wife, comes up with a sweet theory, lands a super-secret government job, has a kid, gets caught up in a communist conspiracy to overthrow America, it's a kinda-sorta-interesting movie about a smart guy, until bam. We learn he's crazy. The roommate, secret government job, and communist plot never existed. Figments of his schizophrenic imagination.
The real brilliant part of this movie is how the one pivotal scene changes the whole frame of reference of the story. We thought it was about some smart guy who makes a theory, but it's really about a man's struggle with his inner demons, with his very conception of reality.
Such is the disad. It's your plan, but with a surprise ending. The story starts out the same (plan happens), but instead of saving the world from poverty, suddenly your plan ends in an economic disaster. Through an cascading series of events, your well-intentioned plan causes some seriously nasty dominoes to fall.
The point that I am making (...eventually) is the most important part of answering disads effectively is knowing the story. What dominoes fall, how exactly do we get from plan to the impact? There are lots of ways you could possibly draw a line between social services and world war 3, so it's not enough just to know where the disad ends up.
Every link that the negative has to use to get to the impact is a liability, for two reasons. First of all, you can prove that this link is wrong (or turn it, win that the opposite happens). But what most novices forget is that you can also win by proving this link is non-unique.
Take a sample disad from last year:
- plan increases alternative energy, let's say by giving tax credits for more wind farms
- More alternative energy means that oil prices will drop because there is a wider global energy supply
- Lower oil prices ruin Russia's economy, which is very dependent on oil
- Russian economic collapse causes a collapse in the government
- Which means a terrorist acquires a nuclear weapon and uses it
Think of how many different Uniqueness claims the negative has to win: that alternative energy is not increasing now, that oil prices won't drop in the status quo, that Russia's economy is doing fine in the status quo, that Russia's government is stable, that terrorists can't get a nuclear weapon now.
They definitely didn't read cards on all of those claims in 1NC. They probably have some evidence on all of those points, but how new is it? Is it any good? Can you find better?
Also, I'm sure that a couple of those cards aren't very specific to wind farms. The "alternative energy -> oil prices drop" card is probably generic to any alternative energy, which provides you with the opportunity to either read a more specific turn (maybe wind in particular raises oil prices? unlikely, but you get my drift) or use a more specific non-unique. The neg can usually be better prepared on their disad of choice, but you should always be more prepared on the specifics of your plan.
Aside from just considering the various links in the story, you also need to think about how their story interacts with yours. If their disad ends in a US economic collapse, how does your plan affect the US economy? You might not be able to prove that your plan "solves the impact" outright, but it's probably true that the neg authors didn't consider whatever positive economic impacts your plan had when they wrote that card. At the very least, if you can win some positive economic effects then you've got a probability argument to make.
That actually leads me to another important point about evidence. 99% of all disads piece together snippets from different articles by different authors who are writing about different things. Occasionally this creates "tension" in the neg's evidence that you can exploit to cast doubt on the disad. For instance, if I sit down to write an article about how the economy is going to recover this year, I want to seem really smart and enlightened. I'm going to pad my article with "even if"s - arguments about how the economy will recover "even if" some bad stuff happens. Maybe I put in a little aside about how the market already anticipates new government spending, so new spending won't trigger a downturn in stocks.
Bam, potential link takeout, right there in the neg's evidence. That example is a little (ok, very) contrived, but pay attention to the neg's evidence and these little contradictions will start to pop out like a magic eye puzzle. They might not always be on the pages the neg reads in round (why you should always track down cites to their killer cards), and they might not be round-winners, but with a little work you can usually carve out some doubt in the neg's story.
And that's really what it's all about in the end. You wanna make your story sound believable and their sound ridiculous, made-up, dumb. Even if he was crazy, Nash still won a Nobel prize, after all.