U.S. Rep. Michele Bachmann (R-Minn.) speaks at a Tea Party Express rally (Creative Commons).

Despite pulling off a number of upsets during the primaries, Tea Party affiliation may end up hurting the GOP’s chances in several close races around the nation.

The Tea Party’s reputation for radicalism and over-the-top stunts – such as Kentucky’s GOP nominee Rand Paul’s supporter stepping on a protester’s head – stands to turn off undecided voters instead of rallying them in before Tuesday.

In California, Republican candidate for governor Meg Whitman hasn't been a Tea Party darling because of her refusal to disavow climate change by completely pledging her support for Proposition 23, which would derail the state's landmark environmental regulations.

But the Tea Party doesn't have any other candidate to firmly back other than little-known Chelene Nightingale. That's left Whitman in a tough spot in the state that pioneered the Tea Party movement.

Political observers guess Whitman, as well as California senatorial candidate Carly Fiorina,  would have liked to move closer to the center to draw the support of indepedents who make up a fifth of California's voters. They tend to lean Democratic, but they can be swayed. The threat of losing support from her base, however, has kept Whitman from appealing to the few moderates that remain in a highly-polarized state. Whitman, who won the Republican primary by 37 points, is poised to lose to Democrat jerry Brown by about five to 10 points.

Whitman has struggled to maintain the support of the Latino vote, as the most conservative elements of the Republican Party push for stronger policies against illegal immigration. She's never quite crossed into the center, running a strategy of keeping the balance slightly to the rate. Her ads constantly remind of the fiscal responsibility mantra dear to the Tea Party.

Elsewhere, the problems for struggling Republican candidates arise from antics as much as semantics.

The Senate race has narrowed even in right-leaning Alaska, where Republican candidate Joe Miller had a commanding lead just two months ago, because of reports one of his security guards handcuffed a reporter and his recent admission to a poll scandal in 2008.

While many Tea Party candidates were able to upend more moderate opponents during the primaries, the lack of moderation is costing the Republicans in both hypothetical and real polls.

In Delaware, Tea Party-backed Christine O’Donnell, whose controversies include witchcraft and the First Amendment, is behind her opponent Chris Coons by an average of 18 points. Had the Republicans nominated Mike Castle, it was predicted he would have beaten Coons by about 11 points. 

Other states with Tea Party implications include Nevada with Sharron Angle, Colorado with Ken Buck and Florida with Marco Rubio. Of these, only Rubio has kept up a comfortable lead.

Although Tea Party supporters are quick to include Republican candidates on their wave of support, not every GOP nominee is as quick to embrace them. Pennsylvania’s Pat Toomey called any connection between him and O’Donnell “fictitious.”

“I don't get this from anyone except members of the press,” Toomey said. “Frankly, I don't think anybody is confused. I've [had] a very clear message for [the last 18 months]. I don't see the issue."

To reach reporter Susan Shimotsu, click here.

Follow her on Twitter: @susanfromtx.