Special elections in the middle of the summer are tricky. Turnout can be very unpredictable.
Race must be close because the national gop put in 500,000.
Some leaked polling has the race at 5 points.
Which way?
The first point above (turnout) is the biggest. It was something like 12%-15% in the primary. If Hackett somehow gets Dems to show up in force (like a third), and the GOP doesn't get above its primary numbers, he can pull off the upset, even with a 2-1 GOP registration advantage.
As to the substance of your fears about how dangerous Hackett is (link is to a collection of blogposts and cartoons on the 2nd District race), I couldn't agree more. He's making Der Schleikmeister look like an amateur.
Just so you know, the MSM has never reported one rather significant FACT about this district: Jean Schmidt received more votes in the primary than the ENTIRE DEMOCRATIC FIELD did.