Detroit files for bankruptcy
Not much to say about this, other than it is merely another example in changing the relationship between employers and labor in the context of a global economy, and how shrinking population, shrinking revenues, and the increased costs that result from abandonment and depopulation and the need to maintain legacy infrastructure constructed for a much larger population.
The "restructuring" of the American steel industry in the 1980s, and the ongoing restructuring of the automobile industry, culminating in the "rescue" of GM and Chrysler in 2009 were indicators of how exogenous changes in the American economy, specifically the rise of global competitors in an inter-connected global economy, meant a change to the relationship between labor and capital.
The same has been happening in cities since the 1970s too, even though there haven't been many examples of actual bankruptcy.
New York City's financial bankruptcy in the early 1970s, DC's bankruptcy in the mid-1990s, Philadelphia's virtual bankruptcy (addressed by then mayor Ed Rendell) presaged the more recent problems of cities in California (like Vallejo), with the addition of other weird problems with cities and counties along the way (Cleveland, Orange County, California; Jefferson County, Alabama; Harrisburg, Pennsylvania) because of bad bad bad dealings, financial engineering schemes that went awry, the Growth Machine wanting to make its way very much known, etc.
-- List of municipal bankruptcies, from Governing Magazine
From "Detroit Files for Chapter 9 Bankruptcy" in Governing:
According to state estimates, Detroit is facing more than $18 billion on debt and unfunded liabilities. Snyder called the city insolvent and announced that "bankruptcy is the only feasible option to fix the city’s finances and do what is right for the 700,000 people of Detroit." He characterized the filing not as a defeat for the city but as an opportunity that will ensure it can focus on improving quality-of-life and growth.
cf. these articles from 2012, "Forget Meredith Whitney, as Muni Lawyer Predicts New Bankruptcy Wave" from ThinkAdvisor and "When Cities Go Bankrupt: Stockton, California" from 24/7 Wall Street