“Experience is an essential strength and indicator of the ability to get things done,” Sen. Ulysses Currie said in a statement. (Patrick Semansky/AP)

Del. Melony G. Griffith (D-Prince George’s) was once considered the heir apparent to state Sen. Ulysses Currie, a 77-year-old son of North Carolina sharecroppers who has served in the General Assembly for 28 years.

But after Currie’s reputation was tarnished by a 2011 federal investigation into consulting fees he received from a Shoppers Food Warehouse in his district, Griffith decided to challenge Currie in Tuesday’s Democratic primary rather than wait for him to retire. The contest is expected to be one of the most competitive in the district since 1994, when Currie (D) was elected senator after eight years as a delegate.

Griffith, a military brat who grew up in Montana, has conducted an aggressive door-knocking and mail campaign, telling voters: “It’s time for a change.”

“Senator Currie laid the foundation for people like me. Without him, many in Prince George’s would not be where they are,” said Griffith, 51. But she added that her experience chairing the county delegation in the statehouse and serving on the House Appropriations Committee would serve her constituents well if she ascends to the Senate.

“Prince George’s is in a fantastic position to leverage resources like its regional medical center and the FBI initiative,” Griffith said. “We need a strong budget leader in a strong position that understands the budget.”

Del. Melony G. Griffith says that Sen. Ulysses Currie, whom she is challenging in Tuesday’s Democratic primary, “laid the foundation for people like me” but that “it’s time for a change.” (Mark Gail/THE WASHINGTON POST)

Community activist Margaret White from the Capitol Heights area was one of several in the county who predicted a close race. But most political observers said they expect Currie to survive the challenge, based on his far superior fundraising, support from the political establishment and unions, and strong ties to the community.

“There are very few upsets in the Senate,” said Senate President Thomas V. Mike Miller Jr. (D-Calvert), a Currie friend and supporter. Griffith “is going to have a tough job unseating him.”

District 25 stretches from impoverished communities inside the Capital Beltway to the posh subdivisions of Mitchellville. It is characterized by its small but vocal super-voters — mostly older residents and African American women, who vote diligently, pay close attention to their leaders and expect results.

Currie has been a responsive and consistent presence in the district, supporters say, leveraging his background as an educator to champion increased spending for schools and early-childhood education. He fought to raise the minimum wage, create programs for welfare recipients and funnel money home as the chair of the Senate Budget and Taxation Committee.

He has inundated homes with literature, attends two to three church services each Sunday and has the backing of Reps. Steny H. Hoyer (D-Md.) and Donna F. Edwards (D-Md.), Lt. Gov. Anthony G. Brown (D) and County Executive Rushern L. Baker III (D).

“Experience is an essential strength and indicator of the ability to get things done,” Currie said in a statement. “As a Senator, I have been able to assist voters with issues big and small, and use my relationships to get results.”

Currie was acquitted of bribery charges in the case involving the fees he accepted from Shoppers Food Warehouse but was censured by his Senate colleagues and stripped of his chairmanship.

“It made the community look bad, and if we reelect him again, it makes us look bad all over again,” said community activist Belinda Quinn-Howard, who is running for the Democratic Central Committee. “It makes District 25 look like we’ll settle for anything.”

But Earle Gumbs, president of the Marlow-Hillcrest Heights civic association, said the episode is in the past and had no impact on Currie’s effectiveness as a leader.

“What was the result of all that?” Gumbs said. “He was found not guilty.”

The question many voters are asking is whether Griffith — who has secured endorsements from area newspapers, including The Washington Post — can be as successful as Currie in bringing home resources.

On the Appropriations Committee, she oversaw tax and pension reforms and protected county projects. She has big plans for investing in county transportation and schools.

But critics say Griffith miscalculated when she opposed plans to build a casino at National Harbor, clashing with other members of the Prince George’s delegation and with leaders such as Baker and Miller.

She said the plan “did not make good business sense,” because the economic and social impact of casinos in the state had not been fully assessed. Health care, Griffith concluded, was a wiser investment.

That independent streak isolates Griffith from some of her fellow legislators, but it is a point of pride for supporters, such as Hollis Lashley of Upper Marlboro.

“Politically astute people in Prince George’s know she cannot be bought,” Lashley said. “She does her homework, and the questions she raises are about how the issue at hand serves the best interests of those she represents.”