WASHINGTON — If New Jersey Gov. Chris Christie has his way, the unfolding presidential campaign will focus on generational fairness. It will seek to curb spending on the elderly — mainly Social Security and Medicare — without putting the elderly at risk. This debate would be good for the country, but whether the country can conduct it without an orgy of bombast and distortion is an open question.

In case you missed it, Christie gave a speech in New Hampshire in mid-April proposing the following:

Social Security benefits would be gradually reduced for those with non-Social Security incomes above $80,000 and ended at incomes exceeding $200,000, a plan Christie said would affect fewer than 2 percent of beneficiaries.

Social Security’s eligibility age would slowly be raised (2 months a year, beginning in 2022) to 69 for full benefits and 64 for early retirement (from the present 62); Medicare’s eligibility age would be raised from today’s 65 to 67 in 2040 and 69 in 2064.

Wealthier retirees with incomes above $85,000, who already pay higher Medicare premiums, would have their premiums raised on a sliding scale so that beneficiaries with incomes above $196,000 would pay 90 percent of the premiums for Medicare Part B (doctors’ bills) and Part D (drug coverage). Presumably, this also would be phased in, though Christie gave no details.

Medicaid — the federal-state health insurance program for the poor — would be cut by putting a ceiling on federal payments to states.

Let’s concede that Christie’s gambit is self-serving. His presidential prospects are said to lag. He strives to differentiate himself from the herd of Republican contenders. What better way to demonstrate “leadership” qualities than to tackle an issue that, according to conventional wisdom, is political suicide. It’s a high-risk/high-reward strategy.

Let me also add: Christie has hedged his bets. He pledges that his proposals would “not affect seniors currently in these programs or seniors approaching retirement.” Why not? Raising eligibility ages now by 2 months a year wouldn’t impose major hardship. Neither would trimming benefits for richer recipients.

Instead, Christie would exempt most baby boomers, no matter how wealthy, from cuts. Boomers’ children and grandchildren would pay for these more generous benefits while their own future benefits would drop.

Christie’s Medicaid plan is also undesirable; it could saddle states with higher costs for long-term care. This could squeeze state spending for schools, roads and other traditional functions.

But the virtue of Christie’s proposal outweighs its vices: A major political figure — and likely presidential candidate — is discussing the central budget problem in refreshing detail. He’s said things that need saying.

To wit: Higher eligibility ages are justified by longer life expectancies. People can and should work longer. Unchecked spending on the elderly threatens “every other national priority,” including national defense. Younger generations face higher taxes, continuous deficits and reduced public services.

But we also need to protect the dependent elderly against poverty. The choices are discomforting.

Can we debate them honestly?

So far, the answer has been no. Rational discussion has been conspicuously absent. Proposals for modest cuts have been portrayed as threatening Social Security’s or Medicare’s very existence. Democrats especially have pummeled Republicans. Christie’s speech might change the context. It creates an opening for reporters and commentators to ask other presidential aspirants — Hillary Clinton and the Republican swarm — how, or whether, they would alter these programs.

We need this debate, however it concludes. It could simply validate the status quo: Don’t touch the elderly’s benefits. Or it could build a political foundation for reasonable cuts favoring the young.

Robert Samuelson is a columnist with the Washington Post Writers Group.