One definition of “tweak” is “small adjustment.” One example of vast understatement is Wisconsin Sen. Herb Kohl’s assessment that “tweaks” are all that is needed to guarantee Social Security’s fiscal sustainability. He offered that absurd assurance last week on a projected $5.3 trillion shortfall in the system over the next 75 years.

As chairman of the Senate Special Committee on Aging, Sen. Kohl should take special care to be more candid about what it will take to save Social Security. And we all should be especially wary about extremely long-range social spending forecasts, which have an expensive tendency to underestimate eventual costs.

Yet citing research by panel staff, Sen. Kohl told The Associated Press, “Modest changes can be made over time that will keep the program in surplus. They are not draconian, as the report points out, and they can be done and will be done.”

“Modest changes”?

Read it all.

It’s easy to look at the protesters and the politicians in Greece ”” and at the other European countries with huge debts ”” and wonder why they don’t get it. They have been enjoying more generous government benefits than they can afford. No mass rally and no bailout fund will change that. Only benefit cuts or tax increases can.

Yet in the back of your mind comes a nagging question: how different, really, is the United States?

The numbers on our federal debt are becoming frighteningly familiar. The debt is projected to equal 140 percent of gross domestic product within two decades. Add in the budget troubles of state governments, and the true shortfall grows even larger. Greece’s debt, by comparison, equals about 115 percent of its G.D.P. today.

The United States will probably not face the same kind of crisis as Greece, for all sorts of reasons. But the basic problem is the same. Both countries have a bigger government than they’re paying for. And politicians, spendthrift as some may be, are not the main source of the problem.

We, the people, are.

Read it all.

The bursting of the real estate bubble and the ensuing recession have hurt jobs, home prices and now Social Security.

This year, the system will pay out more in benefits than it receives in payroll taxes, an important threshold it was not expected to cross until at least 2016, according to the Congressional Budget Office.

Stephen C. Goss, chief actuary of the Social Security Administration, said that while the Congressional projection would probably be borne out, the change would have no effect on benefits in 2010 and retirees would keep receiving their checks as usual.

The problem, he said, is that payments have risen more than expected during the downturn, because jobs disappeared and people applied for benefits sooner than they had planned. At the same time, the program’s revenue has fallen sharply, because there are fewer paychecks to tax.

Analysts have long tried to predict the year when Social Security would pay out more than it took in because they view it as a tipping point ”” the first step of a long, slow march to insolvency, unless Congress strengthens the program’s finances.

Read it all from the front page of yesterday’s New York Times.

But Pimco’s Bond King and Barron’ s Roundtable member Bill Gross contends the relatively high yield on a 30-year bond (compared to a less than 1% on a two-year note) reflects the mounting unfunded obligations taken on by the U.S. government.

In his latest monthly missive, Gross notes the discounted present value of future social-insurance expenditures, mainly Social Security and Medicare, total $46 trillion. The passage of health-care reform will only add to that entitlement.

“No investment vigilante worth their salt or outrageous annual bonus would dare argue that current legislation is a deficit reducer as asserted by Democrats and in fact the Congressional Budget Office,” Gross writes. “Common sense alone would suggest that extending health-care benefits to 30 million people will cost a lot of money and that it is being ‘paid for’ in the current bill with standard smoke, and all-too-familiar mirros that have characterized such entitlement legislation for decades.”

In that regard, Gross cites an op-ed piece in Sunday’s New York Times by former CBO director Douglas Holtz-Eakin, who wrote that rather than reducing the budget deficit by $138 billion over the next 10 years, health-care reform will add $562 billion to the deficit over that span. “Long-term bondholders beware,” he warned.

—Buyer’s Remorse in Bond Market? in last night’s Barrons