Four years ago, the District’s Democratic Party regulars were riding high.

They trooped off to the party’s Denver convention poised to nominate a presidential candidate who not only inspired the city’s reliably Democratic electorate but had pledged to support congressional voting rights. Chances for a solid Senate majority meant the best chance in a generation to pass a bill giving the District a vote in the House of Representatives — its biggest advance in suffrage since the city won home rule in 1973.

Barack Obama won the presidency with 92.5 percent of the District’s vote, and Democrats won a 16-seat advantage in the Senate, but the past four years have seen mostly bitter failure for the D.C. voting rights cause. The disappointment lingers as Democratic leaders arrive in Charlotte to nominate Obama for another four years.

“I think it was a shock to everybody that nothing happened, that with all that going for us, nothing worked out,” said Michael D. Brown, one of two nonvoting “shadow” senators elected to advocate for statehood. “There’s a new feeling we need to do more to make something happen.”

The quadrennial Democratic convention is typically one of the most prominent opportunities for the city to push its voting-rights agenda. But there is a broad sense among local leaders that Democrats have taken the city’s support for granted and that they need to be more aggressive in their advocacy.

Several incidents still rankle: The House voting rights bill ground to a halt in the Senate when 22 Democrats joined Republicans to support an amendment gutting city gun control laws. Obama, shortly before his inauguration, signaled the issue was not high on his “chock-full” legislative agenda, noting its “partisan flavor.” Two years later, to avoid a government shutdown, he agreed to a legislative compromise with Republicans that ended the city government’s ability to fund abortions for low-income women.

Even in preparation for this year’s convention, there have been small-scale snubs.

City leaders, including Mayor Vincent C. Gray (D), have pressed for the inclusion of D.C. statehood in the Democratic platform, restoring language that existed before 2004, to no avail. And while Del. Eleanor Holmes Norton (D) has typically enjoyed a brief speaking role at previous conventions to highlight the city’s struggle for voting rights, this year she has not been offered a slot. In conversations with local party leaders, Democratic National Committee officials have blamed a shorter, three-day program.

Local activists are generally treating the affronts as motivation. “We’ve got to go to Charlotte and make the Democrats step up,” Norton told a pre-convention gathering on Thursday. “We have got to do what we do every single convention. In a political universe where we are small, we need to make ourselves large.”

Delegates and activists have planned a number of ways to raise awareness of D.C. issues. Some will be making breakfast presentations to state delegations. Others are encouraging delegates to wear red T-shirts sporting pro-District messages. Brown and shadow Rep. Mike Panetta (D) have purchased two billboards promoting “statehood now” near the convention site using $7,500 from a city fund for statehood advocacy.

DC Vote, the most prominent group advocating for D.C. voting rights, is holding a Tuesday afternoon rally at Charlotte’s Federal Reserve Bank, a block from the arena hosting the prime-time convention program. The venue, said the group’s executive director, Ilir Zherka, is meant to highlight efforts to win the city more freedom to set its budget independent of Congress — “a smaller step that will be difficult, but is still within the realm of possibility.”

In early summer, a budget autonomy bill that had won support from key Republicans was sidetracked after Sen. Rand Paul (R-Ky.) unveiled several amendments opposed by local leaders.

Zherka said that national Republicans are more openly hostile to District voting rights than at any other time in recent memory, making it crucial that Democrats show the cause strong support. DC Vote, a nonpartisan group, sent representatives to last week’s Republican convention but did not rally supporters there.

“All of us in the movement understand the fight for D.C. democracy has gotten a lot, lot harder in the past few years,” he said. “How do we ensure that Democrats are with us when we need them and not just when it’s convenient to them?”

Besides the four dozen D.C. delegates and alternates, at least 40 additional activists are expected to make the trip. Ward 5’s Democratic organization has chartered a bus to take as many as 80 to Charlotte. “We’re like the D.C. booster club,” said Robert V. Brannum, the Ward 5 party’s president.

Local party leaders say they appreciate any boost D.C. issues can get, as they compete for attention with Obama’s renomination and a host of other matters.

Anita Bonds, leader of the D.C. Democratic Party, admits that she’s “a little bit irritated” at the slow progress on voting-rights issues and Norton’s speaking snub. But she said understands the decision, noting that “it’s easy to get overlooked when you know what color you’re going to be” on the electoral map.

Bonds added that the convention is primarily focused on Obama and his accomplishments. “The things that haven’t been accomplished, the focus isn’t going to be on that,” she said.