One of Washington's best-known legal couples is getting divorced.

Stanley M. Brand and Abbe D. Lowell announced that they are ending their 15-year partnership, dissolving a law firm long known as the go-to litigation boutique for Democrats in trouble. During their years together, Brand and Lowell played leading or cameo roles in nearly every independent counsel investigation and mini-scandal that has roiled the capital. Brand and Lowell said yesterday their union ended amicably and stemmed from a disagreement over the future earnings potential of their firm.

"We had a good racket for 15 years," Brand said. "I'd like to think we enjoyed ourselves, that we had an impact, that we were able to put a small firm on the map."

Meanwhile, two other firms announced that they are getting hitched. Hazel & Thomas, one of Northern Virginia's powerhouse firms, agreed yesterday to merge with Reed Smith Shaw & McClay LLP, a large Pittsburgh-based law firm with a Washington office. Founded by developer John T. "Til" Hazel and Robert Thomas, the 85-lawyer Virginia firm for years has been known for its representation of big-time developers throughout the region.

Pending partner approval of the deal, the firm will be known in Virginia as Reed Smith Hazel & Thomas.

The Brand-Lowell split has been in the offing for months. Lowell, a Bronx-born litigator, said he has been trying to convince his longtime colleague that their 10-lawyer shop needed to link with a larger firm. A merger, he argued, would mean greater resources in terms of both expertise and support staff.

More importantly, clients are increasingly demanding "one-stop shopping" from their firms, and those unable to offer it are missing out on billable hours, Lowell said. "We have clients that come to us for one thing and then have another thing we don't do," he said. "If you can join an entity with more practice areas, more partners and more locations, you're going to find new opportunities for work."

After looking at several firms, Lowell decided to join the D.C. office of Manatt, Phelps & Phillips, a Los Angeles-based firm which has been bulking up its white-collar defense practice and is busily recruiting some of the city's top litigators. Stephen M. Ryan, the other named partner at Brand, Lowell & Ryan, will join Manatt, Phelps, along with three other lawyers from the firm.

The switch is likely to mean a hefty raise. Partners at Manatt, Phelps earn an average of $385,000 a year, according to sources. But with his track record as a rainmaker, legal experts said, Lowell could earn $600,000 or more, depending on how much new business he brings in the door and how well the firm does overall.

The prospect of a fatter paycheck notwithstanding, Brand said yesterday he cherishes his autonomy too much to hop aboard a mega-firm. By remaining small, he said, he can work for clients of his choosing, such as minor-league baseball. Better yet, there's less institutional pressure on him to pull in clients and log billable hours. Brand will remain in the McPherson Square town house that has long housed the firm and will now operate as Brand & Frulla, with partner David Frulla.

"I have thrived in an environment in which I'm allowed to make decisions based on my own lifestyle and motivations and I wanted to retain that," he said.

Though the breakup was caused by an unsentimental business calculation, both men sounded wistful about the end of a union that has rescued more than its share of politicians in distress.

Lowell presented the Democrats' defense of President Clinton before the House of Representatives during the impeachment hearings last year. He has also defended former House speaker Jim Wright (D-Tex.) as well as former Ways and Means Committee chairman Dan Rostenkowski (D-Ill). Regardies magazine once opined that Lowell "may well be the most irritating lawyer in Washington."

Brand has played the mellower, more easygoing part of this duo. He served for years as general counsel to the House and has represented former congressman Tony Coelho and Clinton aide George Stephanopoulos.

For Manatt, Phelps, hiring Lowell is a coup and part of a broader strategy to raise the firm's profile in Washington by hiring marquee white-collar defense lawyers. The firm has deep Democratic ties through its co-founder, former Democratic National Committee chairman Charles Manatt, but it has not yet joined the pantheon of heavy-hitting local firms. With just 52 lawyers and non-lawyer professionals, Manatt, Phelps is smaller than many of its rivals and just 25 years old.

But it's fighting to anoint itself the premier firm for corporations and individuals embroiled in federal investigations. In January, it hired Billy Martin, a well-regarded former prosecutor and more eye-catching hires are expected.

"We're building on our current strength," said June DeHart, managing partner of the D.C. office. "We've got the dream team now."

Staff writer Michael D. Shear and researcher Richard Drezen contributed to this report.

CAPTION: Abbe Lowell, as Democratic counsel, argues before the House Judiciary Committee against impeachment hearings for President Clinton last October.

CAPTION: Stanley Brand drives George Stephanopoulos from a D.C. police station after his client's 1995 traffic arrest. Yesterday, Brand said he would not join one of Washington's mega-firms.