Interesting.
I think the (generous) social security provision is what's missing from the US at-will model.
It ends up smoothing over some of the friction that discourages people from changing jobs, because if you quit your job and take a few months to find another one, you still get a livable salary in between, so there isn't this huge fright of being between jobs that keeps many Americans from jumping even when it would ultimately be advantageous to do so (the fact that you don't lose health care coverage when you quit your job helps too).
In the US, benefits usually run out at 26 weeks. Congress took note of the Great Recession and extended that to 39 weeks, or 48 weeks in states with over-6-percent unemployment, but that extension expires at the end of this year.
And Americans only get unemployment benefits if they are laid off; if you quit or are fired for cause, you’re screwed.
By the way, the max is 73 and 63 weeks (was 99)
http://jobsearch.about.com/od/unemployment/a/unempextension....
Someone who came right out of college, made $50k for two years, is entitled to double digit weeks of unemployment benefits.
Edit: Egg on face. Just looked up the details, while I pay taxes, it seems none of these go towards unemployment insurance, unlike when you're employed, which is why the self-employed don't qualify. Lots of differences from state-to-state too, but in NY it's impossible to "participate" unless you set it up as an s-corp.
There's a hard to quantify cultural element to the difference, which I think is part of what makes it work reasonably well, at least in many cases. The a-kasse project a fairly positive image, of job-finding assistance for people temporarily out of work. People are both assumed to be finding a job in good faith (at least initially), and are encouraged to view the chance of getting one as likely (perhaps with assistance or upskilling). So it doesn't have the same aura of charity/leecher/etc. or dead-endness that Americans tend to associate with welfare (and which even many Danes associate with the "regular" welfare system, e.g. people receiving Kontanthjælp).
There's even some hope that it'll produce a sort of win-win, viewing unemployed people who aren't long-term unemployed as untapped resources that can be used to solve various labor shortages in Denmark. Part of the a-kasse's job is monitoring their sector for what kinds of skills are needed, developing relationships with companies, and figuring out how to plug their unemployed members (perhaps after training) into unfilled needs of those companies.
"flexicurity" is an eupheumism invented by the EU for the central neoliberal tenet "you are now a product". It's not only making it easier to fire someone, it also reduces employees to the subjective opinion of the manager; whether or not you do your job properly is no longer the main issue, your personality is.
The idea is that since you can get fired at whim, you'll be able to get a job faster and you'll be more productive, which is great because the economy is the only thing that matters in today's politics.