Campaign operatives don't have much either, though they at least have access to a lot more data. And so most of them do this: watch the polls and infer back from the polls that the message is or isn't working. Even if messaging ain't what's driving the polls.
We know that the margin between the President and Mitt Romney has tightened over the last couple months and now it's basically a tie race nationally, with the smallest of margins in President Obama's favor. (Obama's doing substantially better in the electoral college.) So, President Obama can't get back into a clear lead, ergo his message isn't working.
It's the same kind of logic that we apply to campaigns in retrospect: show me the losing campaign that people look back on and say, 'Wow, he/she lost but, man, great campaign!' That virtually never happens because losing campaigns were by definition run by morons and all winning campaigns by geniuses.
When a campaign faces head winds, they have to try different messaging. But messaging is usually in an uneven fight with reality. So that means they try different types of messaging in succession. Then they seem confused and floundering. The root isn't that they're idiots. More likely, it's the underlying realities they're up against.
We've had a couple months of disappointing jobs numbers. Today we learned that we've had two straight months of declining retail sales, the first time that's happened in almost two years. Really not good news for the economy or President Obama.
These things matter. They're clearly driving voters' mood (in terms of the underlying economic reality) and their perceptions, since the bad news pervades political coverage.
Obama doesn't seem to me like he's got a clear enough message either. I'd focus on the policies he has that will create jobs and that the Republicans are opposing and then, secondarily, on big picture economic vision. But again, I'm just another commentator with the same difficulties knowing what messaging works or doesn't work. So keep that in mind with everyone.
Don't get me wrong. Campaigns matter, which means that messaging matters. We're just poorly equipped to evaluate how good or effective the messaging is or isn't while it's happening.