If the first day of the general election foretold anything about the rest of the contest, it’s that McCain will be struggling daily to avoid “senior moments.”

Yesterday, McCain had not one but two such moments. At a press conference in New Orleans, he claimed to have voted for every investigation into Hurricane Katrina, when in fact he voted twice against establishing a commission to investigate levee failures. “I don’t know exactly what you are describing at this moment,” he told the reporter. Then, when asked why he called for divestment from Iran but never signed onto the divestment bill Obama introduced last year, he pled ignorance: “I am not familiar with it at all. I do not know if it passed the Senate or had any hearing or anything else.”

Don’t discount superficiality, either. McCain’s age was on display Tuesday as he addressed a few hundred supporters in New Orleans. His speech gleamed on the page, but came off stilted and shaky in the reading. The garish green background and shoddy sound system didn’t do him any favors, either. (A colleague compared it to “bingo night at the hospice.”) Compare that with Obama’s honeyed baritone and photogenic mug addressing a crowd of 20,000, and it almost doesn’t matter what either of them said.

McCain’s in a tough spot. There’s guaranteed to be a double standard when it comes to memory lapses, teleprompter snafus, and other stumbles mental and physical, as the media treats McCain’s pratfalls as part of a larger narrative. (No one blinked when Obama once referred to the “57 states”; if that had been McCain, it would be all over YouTube.) The McCain campaign knows this. That’s why his staffers  released 1,173 pages of the senator’s health records. Also see Mark Salter’s heated response when Obama said McCain was “losing his bearings.” “He used the words ‘losing his bearings’ intentionally, a not-particularly-clever way of raising John McCain’s age as an issue,” Salter wrote. “This is typical of the Obama style of campaigning.”

But if youth and inexperience are fair game, so should be age and too much experience. This year, the first national estimate on cognitive impairment found that more than one-third of people age 71 and older have some diminished mental function. McCain will turn 72 in August. Recall and mental agility are important qualities for younger politicians, too. But with McCain, everyone’s senility-dar will be especially sensitive.