WASHINGTON: Social Security and Medicare long have been considered the nation's fiscal time bombs, and the ticking is getting louder. But presidential candidates Barack Obama and John McCain have no comprehensive plans to overhaul the systems, and are campaigning almost as if they don't notice them.

Medicare faces insolvency by 2019. Social Security is projected to be spending more than it is collecting in taxes by 2017.

Yet both Obama and McCain offer only minor fixes — and few specifics about the modest ideas they do float.

Bigger, bolder, more sweeping approaches are needed, and fast, the experts say.

''They're not preparing the country for sacrifice,'' said Robert Bixby, executive director of the Concord Coalition, a nonpartisan budget watchdog.

The candidates say that they're aware of the gravity of the problem. At Tuesday's debate, they were asked which of three big problems would be their highest priority: health care, energy or reform of the entitlement programs Social Security, Medicare and Medicaid.

McCain said he'd work on all three at once, while Obama cited energy first, health care second — and education third. He didn't mention entitlement reform.

Time works against both candidates.

Beginning in 2011, the first wave of baby boomers — Americans born between 1946 and 1964 — will reach official retirement age. From that point forward, the federal government's finances will be strained, as more and more Americans retire expecting a shrinking number of active workers to pay their promised health and pension benefits.

10-year projection

To put it more starkly: Medicare's trustees project the hospital insurance fund will become insolvent in about 10 years, as its expenditures grow at a 7.4 percent annual rate. The government, the trustees said, will need $342 billion to cover insurance costs during that period.

Social Security is in better shape, but has its own daunting challenges. While it isn't projected to exhaust its resources until 2041, its tax revenue is expected to fall behind outlays beginning in 2017, the trustees said.

The next president will be under pressure to stabilize funding for the two programs.

''The longer action on reforming health care and Social Security is delayed, the more painful and difficult the choices will become,'' said a Government Accountability Office study in June. ''The federal government faces increasing pressures, yet a shrinking window of opportunity for phasing in adjustments.''

Medicare, the report said, ''represents a much larger, faster-growing and more immediate problem than Social Security.''

McCain plans tax credits

McCain's plans for Medicare are part of his overall health care initiative. He'd offer tax credits of up to $2,500 to individuals and $5,000 to families to help offset the cost of health insurance. Premiums for employer-sponsored health care average $12,680 this year, and employees contribute $3,354, according to a Kaiser Family Foundation survey.

McCain said he'd pay for the tax credits with unspecified cuts in Medicare and Medicaid, the state-federal health program for the poor and disabled. The Urban Institute-Brookings Institution Tax Policy Center estimates that McCain's proposed tax cuts would cost the Treasury $1.3 trillion over 10 years. The Arizona senator hasn't detailed how he'd cut that much from Medicare and Medicaid.

McCain would also create a commission to recommend changes.

Obama's plans are similarly vague.

He pledges to ''reduce waste in the Medicare system, including eliminating subsidies to the private insurance Medicare Advantage program, and tackle fundamental health care reform to improve the quality and efficiency of our health care system.''

Obama also backs closing the ''doughnut hole'' in the Medicare prescription drug program. The standard drug benefit includes a $275 deductible and 25 percent co-insurance up to the first $2,510 of prescription costs. Then beneficiaries get no coverage for their next $3,216 in costs. After that, they pay 5 percent of their drug costs.

Analysts find both plans too vague and too small to address Medicare's larger trouble.

''Neither Obama nor McCain has outlined in any great detail any kind of structure change in Medicare,'' said Robert Moffit, director of the Heritage Foundation Center for Health Policy Studies.