When members of Congress and candidates for president bring up the issue of Social Security these days, Americans had better pay close attention – and Californians closer still.

To a degree that would have been unimaginable in the now-gone golden age of retirement, Social Security has become the solitary pillar of support that for about half of today's California workers will allow them to survive on near-poverty incomes rather than become destitute when they reach old age.

A report issued this week by the UC Berkeley Labor Center lays out a startling view of retirement prospects: "Nearly half of California workers – including a large majority of young workers age 25-44 – are projected to lack sufficient resources to meet basic expenses when they retire."

To a large degree, when it comes to retirement security for California workers, Social Security benefits will be nearly all they have.

As of 2009, only 52 percent of workers in the state had access to any type of employer-sponsored retirement plan and just 44 percent participated. Of those who did participate, 61 percent were in a defined contribution plan, typically a 401(k).

In other words, the traditional guaranteed pension has all but disappeared for private-sector workers. And for the relative few who have access to a 401(k), those plans for a variety of reasons have proved to be a grossly inadequate substitute. Most workers insufficiently fund them. Many tap into them for short-term emergencies. And even those who use them as intended have seen their balances ravaged by volatile financial markets.

The rickety reality of retirement insecurity is shown in a pie chart that depicts sources of income for today's retirees, broken down by income class. For the bottom quarter, Social Security and supplemental government assistance account for 90 percent of income. For the middle half, it's 72 percent.

Only for the top quarter of retirees does Social Security function as it is ideally envisioned, as one leg of a three-legged stool. For those in the top 25 percent, Social Security benefits make up only 23 percent of their income.

"Most discussion about Social Security is as if everyone's portfolio looked like that," economist Sylvia Allegretto says. "But you have to go extremely high up the income ladder to get off heavy reliance on Social Security."

Allegretto partnered with three other researchers at the Labor Center to author the chapter of the report that examines California-specific data.

"That pie chart really pops out at you," said co-author Nari Rhee, coordinator of the center's Retirement Security Project. "Social Security provides for a really minimal subsistence. To even be able to meet the most basic expenses, as opposed to teetering on the edge of destitution, you need to have an employer-sponsored retirement plan."

The report discusses some options to re-create one of the missing legs of the retirement-security stool. Among them is the idea of creating a state-run California Guaranteed Requirement Account into which all workers would be required to pay 5 percent of their wages, be guaranteed a 3 percent investment return and then receive an annuity upon retirement that for lifetime workers would provide about 20 percent of pre-retirement income. Employers could voluntarily participate to help workers meet or exceed the 5 percent contribution rate.

That's an idea yet to be explored, and there are no doubt others that will emerge as the public begins to confront what one of the report's contributors calls "the coming age of retirement insecurity."