RICHMOND, OCT. 2 -- Virginia Gov. L. Douglas Wilder sent a sharply worded letter today to Democratic National Commitee Chairman Ronald H. Brown, accusing him and other party leaders of selling out the middle class through their support of the newly negotiated deficit reduction deal.

The letter was the latest salvo in a verbal barrage Wilder has aimed at members of his own party over this week's budget proposal, prompting renewed speculation that Wilder has trained his sights on national office in 1992.

"With whom did you speak before you put the Democratic Party on record in favor of a back-room tax deal which puts the biggest burden on the middle class and those with moderate means?" Wilder asked Brown in the letter, which gubernatorial aides sent to reporters this afternoon.

Brown could not be reached for comment and a Democratic Party spokeswoman did not return phone calls.

The letter struck the same populist theme that Wilder pushed in recent speeches upbraiding congressional Democrats for agreeing with the Bush administration on a package of tax increases and spending cuts designed to reduce the federal budget deficit by $500 billion over five years.

"It is more apparent than ever before that our two-party system is becoming a competition between the party inside Washington and that new party, the vast majority of Americans who live outside who see the need to unite to protect their interest," Wilder wrote.

Wilder has said he expects to serve out his four-year term as governor, which began nine months ago and during which he has made an unprecedented number of out-of-state political trips.

Press secretary Laura Dillard reaffirmed those comments, but other advisers today were clearly relishing the attention Wilder is winning for his attacks on the national political establishment.

"Speculation is a boom business, particularly when it comes to the presidency," said Paul Goldman, a Wilder confidant and chairman of Virginia's Democratic Party. "I've said before I don't think Bush is invincible."

"This latest broadside calls into question his commitment to stay in the governor's office," said Michael Salster, a state Republican activist. "I think it's obvious he's running for national office."

Whatever Wilder's intentions for 1992, he has freely called attention to his own brief experience in Virginia, in which he has implemented or proposed widespread spending cuts to meet a projected $1.4 billion deficit without raising taxes. And Wilder has invited others to follow his approach.

"Washington Democrats had the opportunity to fill the leadership void -- to make meaningful cuts in spending; to tighten the belt around the federal government's all-too-fat waist," Wilder said in a speech Monday at Howard University. "They had that chance, but didn't take it."

In his remarks, Wilder accused the federal government of being "indifferent to the common good and utterly devoid of fiscal common sense."

Wilder's rhetoric, though strikingly conservative for a politician who during the 1970s and early 1980s was regarded as one of Virginia's most liberal legislators, is consistent with his emphasis on "fiscal responsibility" as governor, a tight-fisted approach that has precluded major new initiatives for better transportation or other public needs.

Wilder's attack on Brown is not his first on a fellow Democrat. As lieutenant governor, Wilder had high-profile feuds with then-Gov. Gerald L. Baliles, the first of which came after Baliles backed an increase in the sales tax for new roads.

"Doug Wilder has a long pedigree of anti-establishmentarianism," said Larry J. Sabato, a University of Virginia political scientist. The attack on Brown "is a fine-tuning of Wilder's national strategy."

Wilder, the nation's first elected black governor, may also be in search of a new foil, because Jesse L. Jackson has seemed lately to decline in prominence on the national scene, Sabato speculated.