(CNN) -- The day after President Obama's inauguration, House Speaker Nancy Pelosi described herself as "on a high."
"I am very excited about the prospect of serving as the speaker of the House with President Barack Obama because of the power of his ideas, the strategic thinking that he brings to it and the leadership that he provides to speak to the American people," the California Democrat said.
Obama laid out his agenda for the country and his plan to bring about the change he promised during the campaign. Still glowing from the elections, Pelosi said, "my attitude is to take his lead."
In the 10 months since then, Pelosi has successfully done what she's needed to do to push Obama's agenda through the House -- so much so, that some have asserted she's more effective than the president.
"I think she is a very effective speaker. She can deliver votes. Since 2006, since the Democrats took over, she's consistently been able to unite the Democratic caucus," said Julian Zelizer, a professor of history and public affairs at Princeton University.
Last month, Pelosi cut deals in order to get the Democrats' health care bill passed in the House. She was hands-on in the negotiations, agreeing to a less-robust public option than she originally wanted and allowing a vote on an amendment banning most abortion coverage from the public option. She's also played a key role in getting some of Obama's other priorities through her chamber, including the stimulus bill and the budget.
"Thus far, President Obama -- I think the jury is still out. He doesn't have a huge legislative record, we're still waiting to see what happens with health care. But [Pelosi's] delivered the votes already," Zelizer said.
Pelosi has a longer resume than the president, but it doesn't mean she carries more weight, Zelizer said.
"I don't think she is more powerful than the president; I think she's just been thus far able to deliver the votes that she's responsible for affecting," he said.
Pelosi grew up in a political household. Her father, Thomas D'Alesandro, spent eight years in the U.S. House and was the mayor of Baltimore, Maryland, for another 12. Her brother, Thomas D'Alesandro III, also served as Baltimore mayor from 1967 to 1971.
Throughout the late '70s and '80s, Pelosi held several positions in the California Democratic Party, including state chair from 1981 to 1983. She was first elected to the U.S. House in a June 1987 special election to fill the seat of the late Rep. Sala Burton.
She served on the Appropriations Committee, the Banking and Financial Services Committee, the Committee on Standards of Official Conduct (ethics) and the Permanent Select Committee on Intelligence before taking on the role of minority whip, then minority leader.
When her party took back control of the House in 2006, Democrats elected her as the first madam speaker in U.S. history.
For conservative critics, Pelosi has become a vehicle to paint the Democratic Party as left of center, Zelizer said. "And they have kind of created a caricature of her and made this argument that she's running the show and used it," he said.
Some people see a contrast with Pelosi's ability to run the House and cut deals and the president, who "at times seems to be having more difficulty getting the Democrats together around his legislation," Zelizer said.
Pelosi's also dealing with a different beast. She needs only a simple majority to control debate in the House. In the Senate, Majority Leader Harry Reid needs 60 votes. The president, however, needs both the chambers to reach an agreement on legislation before he can sign it into law.
Thus far, former Rep. Victor Fazio said he'd characterize Pelosi and Obama's alliance as "extraordinarily good."
"There is more thinking as a team, more operating as a majority team than simply the presidency and everybody else," said Fazio, who served in the House for 20 years.
The last time there was a Democratic president and a Democratic House speaker was in the beginning of the Clinton administration, when Tom Foley held the speakership. But in those years, the House was more decentralized and much of the power was in the committee chairs, said Fred Beuttler, deputy historian of the House.
Fazio said that while he thought Clinton and Foley were a good pair, Clinton "never really had the kind of personal rapport with Tom Foley that I see between Pelosi and Obama."
Prior to Clinton, the Democrats last held the presidency and the speakership under Jimmy Carter and Tip O'Neill.
Carter ran his campaign against Congress and Washington and almost went out of his way to snub the speaker, Beuttler said. "That was where the personal relationships really damaged the national agenda."
Fazio recalled a lack of respect between Carter and the speaker. O'Neill referred to Chief of Staff Hamilton Jordan as "Hannibal Jerkin," he said.
Pelosi, however, has a close relationship with Obama's chief of staff, Rahm Emanuel. Emanuel served in the House from 2003 until 2009, when he joined the Obama administration. Pelosi's ties to Emanuel, Fazio said, made it "that much easier to work with the White House."
While Pelosi and Obama don't agree on everything, overall, they have similar agendas.
"I think they understand history very well -- that if the speaker of the House and the president, when they are of the same party, aren't on the same page, then it's very difficult to get things done," Beuttler said, likening their relationship to that of President George W. Bush and Speaker Dennis Hastert.
Hastert rounded up the votes Bush needed and largely able to keep the Republicans together behind Bush's policies during his first term.
But Pelosi and Obama are only a year into their relationship, and there could be potential tension over issues like joblessness or Afghanistan, Zelizer said.
"As midterms are closer or are taking place, if [the Afghanistan] war is deteriorating, if there is no sign of progress, I do think you could have open fighting between the administration and the speaker," he said.
Shortly before Obama announced plans to send more troops to Afghanistan, Pelosi said there was "serious unrest" in her caucus over the cost of the war.
As with Vietnam, there could be funding battles down the road. "During Vietnam it was Democrats fighting against Democrats. It wasn't one party against the other. You could have that again," Zelizer said.
As rough patches come along, Zelizer said it will be important for Obama to continue to nurture the relationship with Pelosi.
"The president is more prominent and has more power, but in the end, every president depends on their legislative allies and the speaker of the House and the Senate majority leaders are the focal points for Democrats in Congress and I think he needs to be careful that the divisions don't grow too severe," he said.
CNN's Eliott C. McLaughlin contributed to this report.