DENVER, COLO. — Forget expectations. Both President Barack Obama and Gov. Mitt Romney walk into their first debate with several significant vulnerabilities that the right question and right answer will either expose or cover. These are domestic policy vulnerabilities, not characterological ones, but they speak to character and mien. We'll start with Obama's trouble spots. 

1. Mortgages. Why didn't he do more to make whole the nation's record number of delinquencies? Why did he bail out the banks and not force them to use the money (because, you know, he did force them to use the money in certain ways) to settle with homeowners? Why have the administration's own programs been mired in bureaucracy? Why did it take him so long to create an investigatory task force on mortgage fraud?  Did he pick the wrong people? If he had done things differently, would the middle class be on a more hopeful trajectory?   

2. Raising taxes. Romney's budget-balancing plan is implausible. But Obama's is scarcely more realistic, given his chief constraint, which is that he will not raise taxes on those families earning more than $250,000 a year. If he sticks to that, whatever Congress does, he is going to have to cut spending by a lot more than he currently intends to. The math for his deficit and debt projections doesn't add up unless all of the Bush tax cuts expire. It's also looking like the payroll tax cuts he trumpeted last year may be forced to go away. Taxes on families who make less than $250,000 a year are going to rise.  

3. Health care. Over and over, Obama reassured those folks with insurance plans they currently like that the Affordable Care Act wouldn't change their health payment arrangements. This was a technical truth that concealed a misdirection. It is very likely that insurance companies, forced to offer new benefits, will raise premiums on plans that are currently affordable; or maybe insurance companies will eliminate certain unprofitable policies, or decide they can't do business with certain companies. It's true that market forces would influence the options offered by insurance companies regardless of whether ObamaCare had passed, but ObamaCare all but guarantees that every major insurance company is going to radically change the menu of plans it offers. Some people might wind up paying less, but some will pay more. Arguably, there is no way around this. Arguably, if Obama had conceded to the American people that ObamaCare would indeed change their insurance policies in the future, the bill would not have passed. I think the White House consciously decided to believe the "technical truth" because the real truth was so politically unpalatable… even though it may have been in pursuit of policies that lead to better outcomes for more people.  

4. Medicare. The Romney-Ryan charge that ObamaCare slashes Medicare has been dealt with elsewhere, but it is true that many health care providers might decide to pass along the costs they must bear to consumers and some, or even a large minority, may start refusing to see Medicare patients altogether because they can't afford to.  

5. Jobs. I don't think there's much Obama can do to create jobs in his second term. I don't think Obama thinks he can create jobs without a major bipartisan deficit reduction plan already in place. It remains a vulnerability because his campaign is (properly) bashing Romney for being vague. Obama has a record, and that record is a proxy for his future intentions, but it is not a sufficient answer to the jobs question. On the other hand, I don't know if there is a sufficient answer to the jobs question.

Later: Mitt Romney's vulnerabilities.