President Obama signed the Patient Protection and Affordable Care Act (commonly known as 'Obamacare') into law, after extensive debate in both Houses, 2½ years ago. It's provisions (which give the USA something vaguely similar to a universal health service for the first time ever) are due to come into effect next January.
However 'Obamacare' is massively expensive and many Republicans are totally opposed to anything which increases US spending at a time when most economists believe that the USA needs to dramatically cut state spending. So they've refused to pass the US budget for the forthcoming year into law unless the Democrats agree to delay the implementation of Obamacare for at least one year (when they'd almost certainly do exactly the same thing again).
Since there's no agreement on the budget, US law requires that all non-essential state services (such as running national museums) are closed down and staff sent home with no guarantee of being paid for the time when they're not employed. Further, the USA will find it far harder to borrow money on the international markets, which will damage their economy (and could quite possibly eventually lead to worldwide economic chaos).
Neither side seems prepared to back down and there's very little 'middle ground', so we could all be heading for a situation far, far worse than that resulted from the banking crisis a few years ago. So perhaps we should all be incredibly gloomy but, as there's nothing we can do about it anyway, we might just as well sit back and laugh at the Yanks for the time being ;-)