FL-16

Republican Tom Rooney:

And here's why:

The Tarrance Group for the NRCC (10/15-16, likely voters, 10/9 in parens):

Tim Mahoney (D-inc): 29 (56)
Tom Rooney (R): 55 (31)
(MoE: ±5.8%)

The Democrats are toast in this district if Mahoney stays in. And I seem to remember something about the incumbent's name staying on the ballot if he does withdraw.