Rep. Donna F. Edwards had a clear message for the small group of constituents who gathered Saturday at an auto-glass store in Lanham: “Protecting Social Security and Medicare and Medicaid are incredibly important, more now than ever before.”

It was the same message she had delivered to multiple audiences over the preceding 48 hours.

Last Friday night, Edwards sent a letter to President Obama signed by 69 fellow House Democrats urging him to keep the programs “off the bargaining table” in the ongoing debt-ceiling negotiations. The day before, on July 7, Edwards surprised colleagues at a closed-door meeting in the Capitol basement when she publicly chastised her Maryland neighbor, House Democratic Whip Steny H. Hoyer, over entitlement reform.

The quick succession of events illustrated what Edwards has become just three years into her congressional tenure — an increasingly prominent voice among liberal House Democrats. Most recently, she has been pressing the White House not to compromise on core party principles for the sake of a debt deal.

“I hope you’ll pardon me occasionally if I nudge the president a little bit,” Edwards said Saturday morning at a bagel shop in Germantown, earning an appreciative laugh from constituents.

The chances of a “grand bargain” on the debt ceiling that might include entitlement cuts now appear remote. But in an interview Tuesday in her Capitol Hill office, Edwards explained why she felt the need to challenge Obama.

“The message coming from the White House [on entitlements] felt like a bit of a surprise,” she said, “and I thought it was really important to respond with a lot of clarity and with a unified voice for our party.”

Democrats haven’t always spoken with a “unified voice.” At last Thursday’s meeting of the House Democratic whip team — Edwards is a member — Hoyer seemed to contradict the message of House Democratic Leader Nancy Pelosi (D-Calif.) by saying that entitlement reform needed to be on the bargaining table.

But Edwards pushed back, telling Hoyer that the leadership didn’t seem to be on the same page, individuals who attended the meeting said. Her tone startled those who attended, particularly given that she and Hoyer are home-state colleagues.

Some Democratic members and aides said privately it was not the first time Edwards has rubbed fellow lawmakers the wrong way — including those from Maryland — by being aggressive.

“I don’t regret what I said,” she said. “I meant what I said.”

Still, Edwards — who only regrets that the incident leaked to the media — apologized to Hoyer the next day before the full caucus, and he accepted. “I apologized very clearly . . . for the tone, but not for the substance. And I did repeat that,” said Edwards, whose 4th District covers much of Prince George’s County and portions of Montgomery County.

Hoyer has been a key ally to Edwards, both in the House and in Maryland. When Prince George’s then-state’s attorney Glenn F. Ivey considered challenging Edwards in the 2010 Democratic primary, Hoyer urged him to stay out of the contest. Ultimately, Ivey decided not to run.

Through a spokeswoman, Hoyer said Edwards is “an effective advocate for her constituents and works hard to represent working families in Maryland.”

Beyond her relationship with Hoyer, 53-year-old Edwards has developed close ties to other leaders as well. When House Democrats held internal elections last November, Edwards was the only lawmaker asked to deliver nominating speeches for three different party leaders — Hoyer as well as Reps. James E. Clyburn (S.C.) and John B. Larson (Conn.) — a sign that they were eager to have her public support.

Edwards defeated Rep. Al Wynn in the February 2008 Democratic primary, after narrowly failing in a similar bid in 2006. She accused the veteran incumbent of being too pro-business and supportive of the Iraq war to represent a solidly blue district.

Wynn unexpectedly resigned in June 2008, after his primary defeat, and Edwards won the special election to replace him a few weeks later.

Edwards was a public interest lawyer and head of a nonprofit that gives out grants for progressive causes before her 2008 victory, when she became the first black woman to represent Maryland in Congress. Edwards, who lives at National Harbor, is divorced and has a son who recently graduated from college.

In her relatively short stint in the House, Edwards has become known as a strong proponent of drawing down U.S. forces in Iraq and Afghanistan. She initially joined other liberals to vote against the Troubled Asset Relief Program, though she backed the financial bailout measure the second time around.

During the health-care debate, Edwards pushed for a provision — one that ultimately made it into the reform law — allowing state insurance commissioners to examine whether individual insurers are excessively raising rates. More recently, she has opposed, along with Hoyer, proposed cuts in funding for the James Webb Space Telescope at the NASA Goddard Space Flight Center in Greenbelt .

Edwards admits, though, that she’s still getting acclimated to the job.

“Because I didn’t come into this as a legislator, I’ve had a lot to learn in a very compressed time frame . . .,” said Edwards, who moved to Prince George’s in the mid-1980s to work for Lockheed at Goddard.

Unlike some of her colleagues in the Maryland congressional delegation, Edwards is rarely mentioned as a future candidate for governor or Senate.

“She’s new,” said Rep. C.A. Dutch Ruppersberger (D-Md.). “You have to crawl before you can walk. She’s developing relationships.”

Edwards has focused on her future in the House. Her close relationship with House minority leaders have earned her a role at the Democratic Congressional Campaign Committee, which is tasked with helping Democrats regain the House in 2012 .

Edwards is one of two lawmakers — Rep. Jared Polis of Colorado is the other — running the committee’s “Red to Blue Program” to support challengers in key GOP-held districts.

“I love the policy, but I like the politics too,” she said.

Many Democrats believe that Republican support for Rep. Paul Ryan’s (R-Wis.) controversial Medicare reform plan could help flip some of the swing districts next November. But if Democrats accede to a debt deal that cuts Medicare, they could lose that advantage.

“To me right now, especially with the Ryan plan, there is a very bright line [on Medicare]. . . . I don’t think there’s any need to muddy the water,” Edwards said.

Edwards’ district gave Obama 85 percent of the vote in 2008. But at both gatherings Saturday, Edwards heard from Democrats unhappy with the White House.

“Our president doesn’t seem to be wedded to Democratic principles,” said Herbert Vital, 47, a Verizon technician from Capitol Heights. “At some point, the Democratic Party is going to have to become the opposition party to our own president and not give him what he wants.”

Douglas Edwards (no relation), who runs the Missions of Love Charities in Capitol Heights, said it was his “prayer that our president will stop trying to be a Democrat and a Republican at the same time. He can only be one or the other. He’s given up too much.”

While the constituents who went to see Edwards on Saturday sounded displeased with Obama, they did not blame their own representative for what they see as his missteps.

“What is wrong with the Democrats’ message?” asked Drew Tucker, 57, an unemployed union electrician from Temple Hills. “When I see you, I thank God we’ve got somebody speaking on our behalf. We don’t hear the president speaking for the liberals.”