Why is Rep. Kendrick Meek struggling in the polls? The St. Pete Times offers its take:

But Meek, 43, has never fully assumed the starring role some thought was his destiny. After four terms, his legislative record tilts more toward rank-and-file than standout.
That reality confronts Meek as he strains for attention in a race dominated by better known and more well-financed opponents who question his effectiveness.
[…]
Meek sided with his party 98 percent of the time in the current Congress. He voted for the stimulus, an energy bill that included a cap-and-trade system to curb greenhouse emissions and the health care overhaul.
He is not a back-bencher by any means, but in a group of 435 members, it is hard to be distinguished. That accounts for the difficulty Meek faces now and the soft embrace he has received from the Democratic machine.