As Walter Olson notes, Ohio is likely today to overturn the public-sector-union reforms the Kasich administration achieved. But I'm similarly pessimistic about the persistence of what Governor Walker has achieved in Wisconsin.
The union special interests have a structural advantage that good-government types don't: the possibility of retroactively undoing the other's accomplishments. For all the political capital expended by Governor Walker in constraining union power over taxpayers, its effects are only prospective. But when the pendulum swings and union-beholden politicians are in the legislature and governor's seat, they can simply repeal these reforms—and worse, provide "makeup" benefits for those "lost" in the interregnum. This is not merely hypothetical: as Michael Greve notes, when Orange County (Orange County!) was able to use bankruptcy to reform its union pension problem in the 1990s, it took just seven years for politicians to agree to retroactively restore the lost benefits.
Unfortunately, the grass-roots movements on both sides of the political aisle—the Tea Party on the right, Occupy Wall Street on the left—are both asking for free ponies and show no inclination to make it easier for politicians to make the tough choices that could fix these problems. One worries that the problem will have to get much worse before it gets better; if so, it will be much more expensive to fix when a sudden run on T-bill interest rates spirals out of control.