The fight for uncommitted superdelegates intensified on Capitol Hill on Wednesday with the realization that the Democratic presidential nomination might remain unsettled until the party’s convention.

Sen. Hillary Rodham Clinton’s (N.Y.) primary victories on Tuesday in Ohio and Texas ensured that the nomination fight between her and Sen. Barack Obama (Ill.) will continue to Pennsylvania, where voters go to the polls on April 22, and then drag on through the summer.

On a conference call with reporters Wednesday, the Clinton campaign argued that the New York Senator has momentum for the remaining contests that also would stop the surge of superdelegates from endorsing Obama. Top Clinton adviser Harold Ickes made the case that many of the outstanding superdelegates will be taking their time to review Obama’s positions and his background.

“We just think that the uncommitted superdelegates or automatic superdelegates will be standing back, keeping their powder dry and waiting for this to unfold,” Ickes said.

The Clinton campaign might be banking on just that, given that the past month has brought numerous superdelegate endorsements for Obama, who until Tuesday had claimed victory in 11 straight primary and caucus contests. Clinton continues to lead in the overall superdelegate chase, but Obama recently racked up several big-name endorsements such as veteran Democratic Sens. Chris Dodd (Conn.) and Jay Rockefeller (W.Va.), and Rep. John Lewis (Ga.), who switched from Clinton to Obama.

But many inside the Clinton campaign believe that movement will slow, and she could even win new endorsements in the coming weeks. Wins in Texas and Ohio could give additional incentive to those who are uncommitted to join up with the New Yorker’s campaign, several Clinton supporters said on Wednesday.

“There’s a universe of superdelegates where there are compelling cases to be made” to endorse her, said Sen. Bob Menendez (D-N.J.), who said he’s working his Senate colleagues as well as his former House allies every day to shore up new support.

Sources close to Obama say the Illinois Senator has been planning a large rollout of endorsements in the coming days, possibly more than 30.

“I’ve been working this on the Member level, nonstop, for weeks,” said Illinois Sen. Dick Durbin (D), Obama’s closest Congressional ally. “And there’s also a universe of non-Congressional superdelegates [I’ve been working]. I don’t know how many of them are still gettable at this point; some will stay neutral all the way to the convention, but we’re going to keep trying to convince people that we’ve got to keep this party together.”

The superdelegate hunt has been in play for weeks, but its importance has been renewed since Clinton is showing no sign of bowing out of the race. Her advisers reiterated her commitment to the contest, with Ickes saying: “We expect this to go down to the wire. We expect this to go down to the end.”

With that reality in mind, the uncommitted superdelegates, especially those representing the remaining primary states like Pennsylvania, are atop Obama’s and Clinton’s target lists. Pennsylvania’s lone Democratic Senator, Sen. Bob Casey, acknowledged Wednesday that while “he’s got a lot of contact” from both campaigns, he won’t take sides before his state’s voters head to the polls.

“I said I’d be neutral throughout our primary, which I will maintain,” Casey said.

“The winner of this nomination will be the president,” Casey asserted. “So, when that much is at stake … we need people in the middle to bring people together.”

Uncommitted Pennsylvania House Members reported similar spikes in contact from the presidential campaigns but also indicated they are taking a wait-and-see approach to issuing endorsements.

Freshman Rep. Jason Altmire (D-Pa.) said the Clinton campaign first reached out to him about 10 days ago when he got a call from the Senator.

Former President Bill Clinton called him on Tuesday and former Secretary of State Madeleine Albright, a top Clinton surrogate, also phoned, but Altmire admitted that he hadn’t gotten around to returning her message. The Obama campaign, meanwhile, has been in “constant contact,” he said.

Altmire said he planned to spend the next few weeks watching and listening to the presidential candidates and figuring out whose message is resonating with his western Pennsylvania constituents. He will then figure out whether he will make an endorsement, and whether he’ll make that endorsement public.

Rep. Mike Doyle (D-Pa.), another uncommitted superdelegate, said he, too, is keeping his options open and hasn’t decided whether he will make an endorsement before the primary. He also joked that he is thinking about changing his phone number due to the increase in calls he’s received.

Doyle argued that the presidential primary continuing is not only beneficial to the party, but it also allows Pennsylvanians to have a say in the process.

“I really can’t remember a time when we’ve been able to see presidential politics up close and personal,” Doyle said, calling it a “New Hampshire-style experience.”

Rep. Robert Brady (D-Pa.), the chairman of the Philadelphia Democratic Party, said he has a meeting on Friday with Democratic city ward leaders, and he will make a decision about an endorsement then.

Numerous Senators and House Members said that while the pressure continues, they don’t feel any incentive to weigh in with two of their colleagues still battling it out for the Democratic Party nod.

“There’s been a lot of talking about endorsing one way or the other, but I feel very confident that we need to let this road continue,” said Sen. Ken Salazar (D-Colo.). “I think most people feel like it’s not necessary to throw one of them under the bus.”

Rep. Artur Davis (D-Ala.), a prominent Obama supporter, argued that Obama has a “hidden reservoir of superdelegate support” that might never become public unless their hand is forced.

“Members don’t like being pressured,” he said. “Members don’t like being pushed.”

The Obama campaign continues to make electability and coattails a plank in their pitch to House and Senate Members. They argue that Democrats downballot will be better off with Obama at the top of the ticket.

Davis also said the best course for the Obama campaign over the coming weeks is not to focus solely on Pennsylvania, although he shouldn’t take the state for granted. He said Obama will be best served by traveling the country and building national support for his campaign and that it would be a mistake to make Pennsylvania — where the demographics heavily favor Clinton — a definitive test.

“It’s not a time to act like he’s running for governor of Pennsylvania,” Davis said.

Sen. Joseph Biden (D-Del.), once a contender for the nomination himself and viewed as a key endorsement for either campaign, said that while he talks to Obama and Clinton frequently, he’s not picking between the two of them. Biden also took issue with any talk that either candidate should step aside now to avoid a protracted primary that climaxes at the national convention in August.

“I think talk about dropping out is ridiculous,” Biden said. “Would you drop out? Of course, what the heck do I know, I didn’t make it to Iowa.”