In my dream presidential debate, the moderator would ask Mitt Romney which tax breaks, exactly, he'd eliminate to pay for his rate cut. The Republican nominee, if history serves, would dodge and demur.

The moderator would try again -- employer-sponsored health insurance? mortgage interest? charitable contributions? state and local taxes? -- and then, in this fantasy scenario, announce that he would wait the allotted 90 minutes for Romney's answer.

This won't happen, though it might make for riveting television. In its place, here are some proposed questions, concentrating on budget, taxes and entitlements:

• President Obama, you have been criticized for not supporting the recommendations of your own fiscal commission. Why didn't you? Do you regret that choice?

You have offered what you describe as $4 trillion in debt reduction over 10 years. Yet your $4 trillion is $2.3 trillion short of what the Simpson-Bowles commission said was essential.

Alan Simpson and Erskine Bowles, your commission cochairs, said your plan "does [barely] stabilize the debt," but "at a dangerously high level and with no margin for error." Are they wrong? Or do you need to do more -- and if so, shouldn't you prepare voters for what this entails?

• Gov. Romney, you have described your approach as "very similar to the Simpson-Bowles plan." Yet the essence of that plan is to reform the tax code to raise revenue and pay down the debt -- not merely to finance lower rates.

Do you believe it's possible to reduce the debt without increasing revenues, either by raising rates or eliminating or curtailing tax breaks -- in other words, not simply through economic growth? If yes, why has every serious commission concluded otherwise -- that a blend of spending cuts and higher taxes is required?

Would you have voted against Simpson-Bowles, as your running mate did?

• President Obama, you promised in Charlotte to take "responsible steps" to strengthen Social Security. Yet in your acceptance speech four years ago you said that "now is the time ... to protect Social Security for future generations," then did nothing on Social Security during your first term. What do you plan to do if re-elected? Would you support Gov. Romney's proposal to raise the retirement age to reflect increases in longevity? To lower the rate at which benefits grow for higher-income seniors?

• Gov. Romney, you have said you want to "reduce federal spending to 20 percent of GDP by the end of my first term" and cap it at that level. You have also said you want to spend at least 4 percent of GDP on defense.

The Center on Budget and Policy Priorities has estimated that, leaving aside Social Security and Medicare, which you do not want to change for current seniors, staying within that cap would require spending cuts of 40 percent in remaining programs.

What will you cut to get to your annual target of $500 billion, beyond lowering subsidies for the National Endowments for the Arts and Humanities, the Legal Services Corporation and the Corporation for Public Broadcasting, which amount to just $600 million a year?

• President Obama, you have denounced Gov. Romney's Medicare plan for putting too much risk on seniors. But isn't the idea of providing subsidies, adjusted for health status and income, to let individuals purchase insurance on well-regulated exchanges, just like Obamacare -- except with a public option in the form of letting seniors buy into traditional Medicare?

Instead, you have said you will fix Medicare by reducing health care costs overall. How? Prominent Democrats, including many who advised you on health care, have proposed steps such as state-based spending caps agreed to by providers, insurers, business and consumers. Would you support this move?

• Gov. Romney, a recent study in the New England Journal of Medicine projects that Medicare costs will grow 1.2 percentage points more slowly than private insurance over the next decade. If so, how would shifting seniors to private insurance save money?

On Medicaid, you would turn the program into a block grant and limit spending growth, cutting $700 billion over 10 years. The Urban Institute has estimated this change would result in lost coverage for between 14 million and 27 million individuals. How can you be confident your plan will not "hurt the people that depend" on Medicaid?

• To both candidates: Why has it taken this long to get answers to these questions?