Was Election 2010 about the tea party or Nancy Pelosi?

The idea of putting largely untested outsider candidates up against even embattled incumbents like Senate majority leader Harry Reid backfired on the tea party Tuesday, potentially costing the Republicans control of the Senate.

With tea party champions Christine O'Donnell in Delaware and Sharron Angle in Nevada both losing their races and Ken Buck in a race still too close to call in Colorado, the Senate remained out of Republican control even as the Democrats faced historic economic headwinds and an angry and dissatisfied public.

To be sure, Republican gains in the Senate – even if short of a takeover – were impressive. Republicans look assured of picking up at least six seats – to 47 – and perhaps seven if Mr. Buck can win his race.

But the failure of Ms. O'Donnell and Ms. Angle – in races that, according to polls, mainstream Republican candidates might have won easily – showed Republicans both the benefits and drawbacks of aligning itself closely with the anti-tax, anti-spending tea party movement.

It helped drive Republican fervor to an a historic pickup of at least 60 seats in the House, but also may have cost the party a firm grip on Congress as a whole – and could yet do the same to a Republican bid for the White House in 2012.

"Ultimately, it's impossible to know exactly how things would have played out had the Tea Party movement not existed," writes Brian Montopoli at the CBS News website. "But it certainly appears that the nomination of both O'Donnell and Angle cost the Republican Party."

Senate races, of course, have a different dynamic than House races. With most states having several – and in some cases dozens – of House races, those races play out on a much smaller scale and often in districts that have been gerrymandered to favor one party. But Senate races, contested statewide, more frequently tend to reward more moderate candidates.

Moreover, on the House side, the rallying cry of "Fire Pelosi" – the successful bid to remove Rep. Nancy Pelosi from her position as Speaker – might have proven more compelling than the bid to oust Senator Reid.

"Losing Nevada is disappointing because it is such an important race and it was held as symbolic," Levi Russell, a spokesman for the Tea Party Express, told the Daily Caller website. "[I]n the broader picture this is a night that is a victory for the Tea Party movement because one of our top opponents since this thing began was Speaker Nancy Pelosi, who we fired tonight."

Nevertheless, even though many seats captured by tea party-backed candidates might well have gone Republican anyway, the movement – comprised primarily of Republicans and independents – fired up conservative ranks and formalized opposition to President Obama and the Democratic-controlled Congress.

"Tuesday saw a wave of Republican red, with the Grand Old Party and its more volatile conservative bedfellow, the Tea Party movement, handed control of the House of Representatives, stripping the Democrats of their treasured majority," writes the Toronto Star's Mitch Potter.

Yet in that lurch to the right lies a difficult challenge for the Republican Party.

"The fact that Tuesday's electorate is far more conservative than the last midterm electorate in 2006 is a sign of how mobilized the right was this year, and the Tea Party had something to do with that," writes the Washington Post's E.J. Dionne. "Yet the Tea Party severely weakened the Republicans in this year's Senate races. It made the difficult task of taking over the Senate impossible."

Certainly, the Republican takeover of the House is by itself critical to shift the balance of power in Washington. And in the Senate, newly elected tea party candidates like Ron Paul and Marco Rubio can have an outsized effect, promising to severely hamper President Obama's ability to push through major legislation. "The ability of this administration to get major new programs done was already limited. This [election] just seals the deal," Jaret Seiberg, a policy analyst with the Washington Research Group investment advisory firm, told Reuters.

But others see the failure of the GOP and the tea party's role in that predicament as a sign that the tea party penchant for putting forth candidates like O'Donnell and Angle will ultimately hurt the GOP's chances of wresting control of Washington.

"The lesson, if Republican activists choose to accept it, is that similar [tea party] extremism ... could cost Republicans the White House in 2012," writes columnist Joel Connelly in the Seattle Post-Intelligencer.