AS CHAIRMAN of Prince William County's Board of Supervisors since 2000, Sean T. Connaughton has managed the growing pains of one of the nation's most dynamic suburbs -- a sprawling locality of 352,000 people generating new jobs, neighborhoods and wealth at a staggering rate. The first Republican to hold the county's top elected office, Mr. Connaughton, 44, a former Navy patrol boat commander, has navigated a course between property developers, environmental groups and homeowners that would have sidetracked and stymied many officials. Now he is a candidate in next Tuesday's GOP primary for lieutenant governor, and we endorse him enthusiastically. He is among the more promising and impressive young politicians in some time to seek statewide office in Virginia.

A maritime lawyer, Mr. Connaughton is a member of that increasingly rare breed: a moderate Republican in Virginia. Like a majority in his party, he favors the rights of gun owners, opposes abortion and favors the expansion of faith-based social programs. But when it comes to paying for the state's overwhelming needs for new roads and public transit infrastructure -- probably the greatest challenge the commonwealth faces in the next decade -- he is honest and pragmatic enough to consider all options, including the possibility of new tax revenue. "I don't rule out anything," says Mr. Connaughton, who stresses that he would first seek transportation funding through tolls and the state's existing general revenue. That sets him apart from his GOP primary opponent, state Sen. Bill Bolling of Hanover County, a suburb of Richmond. A hard-line ideologue, Mr. Bolling has imprudently tied his own hands by signing a pledge to oppose future tax increases.

Mr. Connaughton has what most of this year's other primary candidates in both parties lack: executive experience in public office. On his watch in Prince William, Virginia's second most populous county after Fairfax, the county has built 18 schools, hired hundreds of police officers and firefighters, and undergone demographic shifts that will soon make blacks, Hispanics and Asians a majority of the population. At the same time Prince William has upgraded its credit rating to AAA, one of only a few dozen counties in the nation to attain that imprimatur. Under challenging circumstances, Mr. Connaughton has astutely overseen an annual budget of $765 million, balanced job growth with the preservation of rural areas and pushed for the construction of new roads and schools to serve new neighborhoods. Inevitably, he has ruffled feathers by taking sides in heated disputes over development, but when he has done so, his comportment has been civil and decent. Although we reserve judgment in November's general election race for lieutenant governor, Mr. Connaughton is much the superior Republican, and we hope he receives the party's nod in Tuesday's primary.