Since I disagreed with Ezra Klein earlier today, and since I don't often get the opportunity to agree with him, I should note that I'm basically with him on one of the biggest problems with deferred compensation in the public sector: "Workers think their pension is a fact when it's really just a promise—and promises can be broken." That's especially true when you bring the vagaries, rivalries, and petty disputes that drive most of our country's politics into the equation.
I'd add, however, that the broken promises of politicians are also something more people should think about when it comes to another realm of domestic policy: entitlements, especially Social Security. As Cato's Michael Tanner pointed out last year, one of the problems with the current Social Security system is that "workers have no ownership of their benefits. This means that they are left totally dependent on the goodwill of 535 politicians to determine what they'll receive in retirement." In other words, when the government makes promises about what it will do in the future but subjects those promises to the political process, it's usually a good idea to be wary.