In 1962, we were laying down the foundations of prosperity. About 32 cents of every federal dollar, excluding interest payments, was spent on investments, only 14 percent on entitlements. In the mid-70s the lines crossed. Today we spend less than 15 cents on investment and 46 cents on entitlements. And it gets worse. By 2030, when the last of us boomers have surged onto the Social Security rolls, entitlements will consume 61 cents of every federal dollar, starving our already neglected investment and leaving us, in the words of the study, with “a less-skilled work force, lower rates of job creation, and an infrastructure unfit for a 21st-century economy.”

Some of the entitlement bloat comes from the addition of new programs — notably the prescription drug benefit espoused by our second boomer president, George W. Bush, and the Affordable Care Act, though at least that law sets in motion offsetting measures aimed at containing the soaring cost of health care. Some of the growth is built into formulas that increase benefits faster than inflation or G.D.P. And a lot of it is us: boomers, aging into Social Security and Medicare. “We’ve reached the point where our working-age population over the next 30 years grows by one-fifth, and our elderly population grows 100 percent,” said Jim Kessler, the senior vice president for policy at Third Way.

Indignant readers are already revving up to tell me that Social Security and Medicare are sacred promises, that cutting them would be stone-hearted Republicanism. A.A.R.P., the lobby for people we used to call senior citizens until we realized that meant us, got hammered by the left earlier this year when its C.E.O. dared to convene a meeting of Washington insiders to even discuss the subject. No wonder A.A.R.P. shies away from supporting any entitlement reform.

But the traditional liberal alternatives — raise taxes on the well-to-do, cut military spending — are not nearly enough by themselves. The arithmetic simply doesn’t work, unless we face the fact that entitlements are a bargain we can’t afford to keep, not in full.

So the question is not whether entitlements have to be brought under control, but how. The Republican plan espoused by Mitt Romney and his fiscal lodestar Paul Ryan would cut the cost of entitlements largely by moving toward privatization: personal investment accounts for Social Security, vouchers for Medicare. And it’s not at all clear the Republicans would assign any of the savings to investing in our future.

At least the Republicans have a plan. The Democrats generally recoil from the subject of entitlements. Centrists like those at Third Way and the bipartisan authors of the Simpson-Bowles report endorse a menu of incremental cuts and reforms that would bring down costs without hitting the needy or snatching away the security blanket from those nearing retirement. They include gradually raising the retirement age to compensate for the fact that we now live, on average, 14 years longer than when F.D.R. signed Social Security into law. They include obliging those of us who can really afford it to pay a larger share. They also include technical fixes like aligning the automatic cost-of-living formula with reality. To curtail the raging inflation of health costs, the government could better use its market clout to hasten electronic record-keeping, replace the fee-for-service model, reform medical malpractice laws and promote living wills. (A quarter of health care spending comes in the last year of life.) But you won’t hear much of that on the campaign trail.

FELLOW boomers, we have done more than our share to make this mess. It’s not our fault that there are a lot of us, but we have resisted any move to fix the system. We should make a sensible reform of entitlements our generation’s cause. We should stiffen the spines of our politicians, and push lobby groups like A.A.R.P. to climb out of the bunker and lead. (And, by the way, we should resist the boomer temptation to take every cent of the reform from the pockets of our kids.) We should keep the heat on Congress and the president to double down on the cost-saving provisions in Obamacare.

We may not be the greatest generation, but we are the largest — and we vote. We throw our weight around. What if we threw some of it in the right direction?