Political prognosticators lay out the worst-case scenarios for Democrats and Republicans in November

Democrats are hoping the often-times more conservative, Tea Party-backed candidates who won GOP primaries scare off enough voters to prevent Republicans from winning seats they should be able to pick-up or retain in states like Nevada, Florida or Kentucky.

“When we talk about what kind of an impact the Tea Party is going to have on the midterms, what I’m watching are these seats where the Tea Party has nominated candidates over more viable Republican candidates,” Jennifer Duffy of the Cook Political Report told The New York Times recently. “That’s my measuring stick.”

Before this summer, for example, it appeared that Republicans had the open Florida U.S. Senate seat locked up in their column. But after candidate Marco Rubio consolidated the conservative, Tea Party support, his primary opponent, Gov. Charlie Crist, left the GOP to run as an independent, dramatically increasing the chances that either a Democrat or an independent candidate could be elected.

In Nevada, Republican Sharron Angle — ardently supported by many in the Tea Party movement — is running neck-to-neck with Senate Majority Leader Harry Reid. It’s widely believed that the very-unpopular Reid would be trailing any of the other top Republican challengers eliminated in the GOP primary.

National Democrats have made it an integral part of their November strategy to vilify the so-called Tea Party-backed Republicans and marginalize them as outside the mainstream. If that strategy works — and keeps competitive seats from going to the GOP — the Tea Party could be blamed.

“It could be the difference between getting the majority or not,” Duffy said.