He just doesn't have the money. He decided to take public financing and that will hobble him versus the Republican machine if he's the nominee.
In Iowa, Edwards had a major TV presence only with the assistance of third-party ads paid for by unions and by a group fronted by his ex-campaign manager. The Obama and Clinton people see this lack of cash as a key vulnerability.
If Edwards is to survive beyond the first several states, no matter how he places in Iowa on Thursday, his campaign will rely heavily on its supporters from organized labor.
Unions representing more than 3 million members have endorsed Edwards, and labor volunteers have been crucial to his get-out-the-vote efforts in Iowa and New Hampshire.
His aides sought to underscore that union strength, saying it was more useful than the large numbers of offices or staffers.
"The union will do it" is not a statement of strength. It is weakness. You can be on the right side of every issue, if you haven't got the cash it's almost impossible to dance.