There is little doubt these days about whether Sen. Hillary Rodham Clinton (D-N.Y.) can be nominated and then elected the first female commander in chief. Republicans and Democrats alike believe that she can.

But privately some Democrats — along with gleeful Republicans — are examining this question: Could the polarizing former first lady win the White House in 2008 but end up costing her party seats in Congress downballot?

Clinton allies argue that she has proved her appeal in Republican-friendly terrain — upstate New York most notably — and other Democrats believe that the name at the top of the ticket won’t ultimately matter.

“It’s impossible to predict the impact one particular candidate will have,” said Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.).

However, some of the most vulnerable House Democrats next year are freshmen who rode the 2006 Democratic wave to victory in states and districts that traditionally favor the GOP, especially in presidential years. Freshman House Members such as Nancy Boyda (Kan.), Jerry McNerney (Calif.), Zack Space (Ohio), Heath Shuler (N.C.) and Christopher Carney (Pa.) represent very conservative electorates.

Could having Clinton at the top of the ticket further jeopardize those seats as well as more veteran Democrats such as Reps. Baron Hill (Ind.), Jim Marshall (Ga.) and John Barrow (Ga.), top targets who are all but certain to face difficult re-elections in states that will not be contested on the presidential level?

“Having her at the top of the ticket is just as polarizing as [President] Bush at the top of the ticket, even though the electorate right now is looking for a less polarizing figure,” Florida-based Democratic consultant Dave Beattie said.

Beattie said he believes Clinton can be elected president but if she competes in and wins largely the same states that Sen. John Kerry (D-Mass.) did in 2004, she could have an adverse impact downballot on Democratic Members and candidates in states that aren’t competitive on the presidential level.

“I think that the problem with Hillary is there is a caricature of Hillary Clinton among conservative voters. Her campaign is about countering that caricature,” Beattie said. “But where the caricature is strongest, where it’s going to hurt the most, they’re going to be doing the least to counter it.”

Still, many Democrats say, “Not so fast.”

Rep. Earl Pomeroy (D-N.D.), who has won re-election since 1992 in a state that overwhelmingly favors the GOP in presidential elections, spoke very favorably of Clinton and noted that Republicans were attacking her awfully hard for someone they say they would prefer to run against.

“It’s way too early to conclude that Hillary would be a disaster downballot for the party,” said Pomeroy, who is still mulling a 2008 endorsement.

To be fair, Clinton’s top rivals for the Democratic nod — Sen. Barack Obama (Ill.) and former Sen. John Edwards (N.C.) — carry their own liabilities with conservative voters and it’s debatable whether having either man at the top of the ticket would help vulnerable Democrats fare any better.

However, neither has as controversial a persona as Clinton, best known to the national audience of voters from the eight years she spent as first lady.

“I think it’s harder for Hillary Clinton to overcome general stereotypes about Hillary Clinton than it is for Barack Obama to overcome stereotypes about a black man,” Beattie said.

National Republican Congressional Committee Chairman Tom Cole (Okla.) said the new Democratic majority’s record and the increased GOP turnout because of the presidential race in those conservative districts would be more of a deciding factor in House races than the Democratic nominee would be.

“I think it matters that it’s a presidential year, I don’t think Hillary Clinton matters,” he said. “I don’t think Barack Obama or John Edwards would make any more difference come Election Day than Hillary Clinton.”

Privately, however, Republican strategists look at the 2008 battleground map and instantly have visions in their heads of Clinton-themed TV ads and attack-mail pieces targeting vulnerable Congressional Democrats.

“It’s a huge motivator for our base,” said one GOP operative. “Keep in mind where we need to win. We need to regain Republican territory and in those particular districts our base is larger than theirs is.”

Not surprisingly, backers of Obama and Edwards seem to agree.

Rep. Artur Davis (D-Ala.), an early supporter of Obama and also the recruitment chairman at the DCCC, said vulnerable Members in Southern states have expressed private concerns about the top of the ticket.

“They think Barack Obama would be stronger in their district than Hillary Clinton would be,” Davis said, asserting that the Illinois Senator has the broadest appeal, while Clinton’s strength is with rank-and-file Democrats.

Edwards, meanwhile, is campaigning on electability and vowing to expand the 2008 battleground into Southern territory.

“Unlike other Democrats, who will be forced to ‘run the table’ of states where Democrats have been competitive in recent elections, Edwards brings new states into play,” Democratic pollster Harrison Hickman wrote in a polling memo prepared for the Edwards campaign. “This provides alternative scenarios — and a margin for error — when it comes to winning 270 electoral votes.”

Still, while the one-term Senator from North Carolina might appear on paper to have the best-selling assets in conservative states, his campaign has focused on liberal and populist themes that put him to the left of his two major rivals. He has renounced his vote in favor of authorizing the Iraq War and said he doesn’t believe there is a global war on terror — not a message that resonates well with the conservative Southern electorate.

“Edwards has the best demographic profile in the general election, but he will end up having the least sellable ideological profile in the general election,” noted one GOP consultant.

Supporters of Clinton argue against underestimating her ability to do well with more conservative voters.

“She’s very good with rural voters,” said Rep. Kirsten Gillibrand (D-N.Y.). “She’s spent a lot of time in upstate New York, she understands farmers.”

House Democratic Caucus Chairman Rahm Emanuel (Ill.), the past DCCC chairman and an architect of the party’s 2006 success, noted the reverse of the Clinton question is the possible effect the Republican nominee will have in the Midwest and the Northeast, two areas where Democrats saw their largest Congressional gains in the previous cycle.

“There’s a cost-benefit to everything,” said Emanuel, who is publicly neutral in the White House race.

Clinton’s ability to motivate the Democratic base and appeal to independent voters — especially women — could wind up further endangering some Republicans in swing seats and helping Democrats protect the massive gains the party made in the Northeast and Mid-Atlantic in the previous cycle.

“I think in red states that Hillary would lose in any case, I think it does have a real impact in downballot races,” said the GOP consultant. “In the strong blue states, it could have a positive impact.”

Rep. Mike Ross (D-Ark.), a leader in the conservative Blue Dog Coalition, endorsed Clinton recently and noted that when she came to keynote the Arkansas Democratic Party’s major fundraiser last month, 4,000 people showed up to an event that usually draws 1,000.

He also believes that Clinton is appealing to more moderate independents who are fed up with Republicans.

“I think she’s going to bring a lot of independent voters who have voted for Republicans back to the party,” he said.

Rep. Lincoln Davis (D-Tenn.), who has not endorsed any of the candidates, put it this way: “I’d a whole lot rather have to defend Hillary Clinton than George Bush in my district.”

Still, he’s holding out hope that former Vice President Al Gore, a Tennessee native, eventually will enter the race.