And trying to cut benefits buys intense opposition.
"It's nothing new: It's human nature," said Robert Strauss, an economist at Carnegie Mellon University's Heinz School of Public Policy, who is an expert on public finance. "Back to pre-democratic times, those in charge have liked to make people happy by giving them things financed by long-term debt."
This dynamic helps explain why even states that have made pension changes, such as Gov. Christie's New Jersey, are still projected to fall far short of the savings they have promised.
States were $1.38 trillion short of having enough to pay their public-employee retirement bills in 2010, the last year for which totals are available for all 50 states, according to the Pew Center on the States. That was up 9 percent over the previous year.
Between 2009 and last year, 44 states enacted changes to their pension systems, such as requiring higher employee contributions, making benefit formulas less generous and raising the retirement age, according to the National Conference of State Legislatures. Eighteen, including New Jersey, reduced or eliminated cost-of-living allowances in pensions.
The problem's roots go deep. For years, experts say, many states increased benefits to buy labor peace and skipped making required contributions to pension funds when times got tight, hoping that the performance of those funds' investments would make up the difference.
Corbett says the two Pennsylvania public pension plans, for state workers and school employees, are underfunded to the tune of $41 billion. The Republican governor is pushing to cut benefit levels for future retirees - not current ones, as he often points out - but has not released a specific plan. Nonetheless, the legislature has not appeared enthusiastic to act, and the public-employee unions are mobilizing.
They note that workers have contributed to the solution, in the form of future cuts in pension benefits, and say the state must stop skimping on its payments into the funds.
"The employees never skipped a payment," said Ted Kirsch, president of AFT Pennsylvania, one of two major teachers' unions in the state.
The need to find a way to fund the growing cost of all those pensions is real, pollster Terry Madonna of Franklin and Marshall College warned - "the state is sitting on this volcano."
And yet, he said, the volcano goes unnoticed by the villagers. Pension reform has not emerged as an explosive issue that moves voters, though that could change as the "tapeworm" keeps eating into the state budget, and retiree costs begin pushing out other discretionary spending in earnest.
"If you're an average voter, and not a state employee or teacher, this is not something you're lying awake worrying about at night," Madonna said. "It's not a top-of-mind issue. You're not pounding on your legislator to fix it."
Corbett's situation is complicated by his weak political standing, as shown in two independent polls released last week that found a third or fewer Pennsylvania voters approved of the way the governor is handling his job. He has taken damage from a series of setbacks - state Attorney General Kathleen Kane's rejection of his plan to privatize management of the state lottery; lingering criticism, stoked by Democrat Kane, of his handling of the Jerry Sandusky sex-abuse investigation at Penn State; the continuing legal fight over the voter ID law he championed; and lukewarm legislative support for his ambitious plan to get the state out of the liquor business, a cause that has confounded several of his predecessors.
Taking on pension costs is "going to be very controversial along with everything else he's thrown out for the legislature to consider," said Nate Benefield, director of policy analysis at the conservative Commonwealth Foundation in Harrisburg. "The House leadership wants to get liquor privatization done first, and some senators want more money for transportation," he said. "A lot of it is, 'We're going to drag our feet until we can get what we want.' "
Plus, "It's easier to push off the cost into the future if you can," Benefield said. "What's the incentive to do otherwise?"
As a sign of how difficult the issue is, Nutter has asked the state Supreme Court to impose the city's contract terms on its biggest employee unions after four years of talks without an agreement. Philadelphia's proposal includes higher pension contributions from workers and a partial shift to a 401(k)-style plan.
On Thursday, the unions' power was on full display in the City Council chamber, when hundreds of union activists packed the galleries and overwhelmed the beginning of Nutter's budget address with whistles and chants. Council adjourned early and Nutter delivered his message in a reception room closed to the public.
Nutter, in his second term, won't face voters again unless he seeks another office. Analysts point out that the unions can outlast him - and use their sway to strike a deal with a candidate in the 2015 Democratic primary for his successor.
In 2011, New Jersey raised government workers' pension contributions from 5.5 percent of pay to 6.5 percent, with a gradual climb to 7.5 percent by 2018. Contributions rose to 10 percent from 8.5 percent for police and fire employees. The state also did away with automatic cost-of-living adjustments to pensions.
"There was a political will," said Ben Dworkin, a political scientist at Rider University who studies New Jersey politics.
"One of the reasons these things get put off so long is that it never reaches a crisis point," he said. "We talk about 'unfunded liability,' billions of dollars, but it's not happening yet. People don't all retire on the same day."
Dworkin said Christie made the state's retirement liability a priority and found common ground with State Senate President Stephen Sweeney (D., Gloucester), who also was concerned. They rounded up South Jersey Democrats who were willing to defy the public-employee unions and join with Republicans to get the changes passed.
Still, actuaries have said New Jersey's system, while on better footing now, remains underfunded.
But it's better off than in Illinois, which is underfunded by about $98 billion. Quinn, the governor, has been unable to get anything through his legislature - despite Squeezy.
"Ultimately, what will change things is capital-market discipline that puts a crimp in government borrowing," said Carnegie-Mellon's Strauss. Governors and mayors needing to fund pension plans will have to turn instead to taxpayers and future retirees.
When that day comes, Strauss said, "there's going to be conflict."
Contact Thomas Fitzgerald
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