Here's one thing the two presidential candidates agree on: the federal government's current fiscal course will lead to disaster.
They both even genuflect to the same starting point for a possible compromise: the 2010 proposal offered by former Sen. Alan Simpson (R-Wyo.) and Erskine Bowles, President Clinton's former chief of staff.
"I think very highly of their recommendations," Mitt Romney said last spring.
"I'm still eager to reach an agreement based on [their] principles," President Obama said at the Democratic National Convention.
So does this mean the candidates agree on how to fix the budget? Hardly. They don't even really agree on the Simpson-Bowles proposal.
When Simpson and Bowles were looking for support in 2010, Obama and Romney were nowhere to be found. Obama greeted their proposal with little more than a perfunctory thank you, and he was the one who had named them co-chairmen of his budget commission. Romney was mostly silent on their report, but his running mate wasn't: Paul D. Ryan voted against the proposal as a member of the commission.
There's plenty of pain in the Simpson-Bowles proposal, of course; that's why it united the two parties in the House of Representatives in a rare moment of bipartisanship when they voted against endorsing it by a whopping 382 to 28.
The proposal would slash both domestic spending and defense spending, and raise taxes to boot. It would cut benefits for the elderly, veterans and government employees and impose a cap on future healthcare spending. And it would gradually raise the Social Security retirement age from 67 to 69.
Obama has proposed a budget plan with spending cuts, but they are far lower than the cuts Simpson and Bowles propose. Romney, who would cut domestic spending deeply, claims that his own tax proposal is similar to Simpson-Bowles, but it's not even close. Simpson and Bowles would increase taxes to raise federal revenue, but Romney has promised never to raise taxes.
And neither candidate has been courageous enough to suggest future cuts in Social Security benefits.
But let's give both candidates the benefit of the doubt and assume that they really do embrace the logic of Simpson-Bowles: that both sides must make painful concessions.
Which presidential candidate is most likely to succeed in forging a compromise?
I went to Simpson and Bowles themselves last week for an answer. They didn't make it easy.
"Neither candidate has been specific enough in telling the voters how they'd do it," said Simpson. "You're going to have to flip a coin."
"I will be voting for Mitt Romney. And Erskine will be voting for Barack Obama. And then we'll move on," he said.
Still, the two prophets of budget balancing framed their choices in ways that may help voters decide.
Simpson's case in favor of Romney boils down to this: "Romney knows how to govern. How do you learn better to govern than by being governor of Massachusetts, working with a Democratic legislature?" Obama, he said, "hasn't made the tough decisions."
Simpson isn't happy about Romney's refusal to increase tax revenue, and he wishes his candidate hadn't signed anti-tax crusader Grover Norquist's pledge that he'd never raise taxes. Nor does he like Romney's proposal to increase defense spending. "Our defense budget is already bigger than the next 15 countries combined," he said. "Who are we kidding?"
What about Bowles?
He says he supports Obama, largely because he thinks a second-term president has more freedom to compromise. "It's just common sense," argued Bowles. "A second-term president who is not running for reelection, who doesn't have to worry as much about what the base thinks, is more likely to do a deal."
On the other side, he said, "Gov. Romney has staked himself on no revenue increases to prove he's a real conservative. He said he wouldn't agree to $1 in revenue in exchange for $10 in spending cuts. It would be very difficult for him to move away from that." (The Simpson-Bowles proposal calls for $1 in revenue for every $3 in spending cuts.)
Still, Bowles says he isn't happy about big parts of Obama's platform. He thinks Obama doesn't cut future spending on healthcare deeply enough, and he doesn't agree with the president's proposal to raise tax rates on high-income taxpayers.
But he said Obama has convinced him that his commitment to solving the problem is real.
Fixing the federal budget is the most important domestic challenge facing the next president. And that makes one question crucial: Which candidate has the courage, backbone and skill to make a deal?
Follow Doyle McManus on Twitter @DoyleMcManus