The Loudoun County Board of Supervisors' about-face on whether to let voters choose the board's chairman taught a painful lesson to some supervisors and demonstrated how rapidly politics is changing in the county.

In opposing a November voter referendum on the issue, then weathering an immediate protest and quickly reversing themselves, county supervisors discovered they can no longer count on constituents buttonholing them on the sidewalk or writing letters to keep them abreast of the public's mood.

"Life's a two-way street," said board Vice Chairman Charles A. Bos (D-Leesburg District). "I learned that I've got to keep reaching out."

In some ways, Loudoun's political transition has been startling. Just three years ago, when the current board was elected, Loudoun was a smaller, more close-knit community, and serving on the Board of Supervisors was the part-time job it was designed to be.

Now, the board and the county administration are almost overwhelmed by a constant stream of crucial policy and land-use decisions.

"Folks, we've got a whole bunch of stuff on our plates," said board Chairman Betty W. Tatum (D-Guilford).

Recent arrivals to Loudoun, some with less interest in local government than longtime residents have, make up an increasing share of the county population. No one is sure how they will vote.

As bulldozers continue to turn cornfields into subdivisions and office parks, the supervisors will use census data to carve the county into new political districts next year before they run for new four-year terms, adding to electoral confusion.

Meanwhile, increased use of computers to update voter lists and to target fund drives, more aggressive strategies by the local GOP and a larger news media presence also are reshaping the political landscape in the county of 90,000.

The most visible sign of change has been the debate over whether the county board chairman should be selected by the eight district supervisors from among their ranks, or by adding a seat for a chairman to be chosen by county voters.

Letting voters select the chairman has been urged by state Sen. Charles L. Waddell (D-Loudoun) and a board-appointed commission as a way of giving the voters more say in government, increasing efficiency, fostering leadership and avoiding tie votes.

For example, the Loudoun board, with six Democrats and two Republicans, has been deadlocked 4 to 4 for five months on where to build a county government office complex.

The D.C. Council chairman is elected by voters, and in Fairfax County the voters choose the board chairman. Switching to that system in Loudoun would make the new chairman a county spokesman with a comparably high profile who would not be tied to the parochial politics of a particular district, backers argue.

"Whether we wind up with an Audrey Moore or a Jack Herrity, at least we'll wind up with someone with a clear mandate for four years," said Loudoun Supervisor Steve W. Stockman (R-Broad Run), referring to the current and former Fairfax board chairmen.

Several Loudoun supervisors were angry at Waddell for threatening to back a petition drive to put the issue on the ballot if the supervisors did not.

Despite strong support for the ballot question by the board-appointed Blue Ribbon Commission, Tatum and five other supervisors voted against it, saying they would switch their votes if the public spoke up for the ballot issue. Only Stockman and Supervisor Betsey Brown (D-Catoctin) backed the referendum.

Within a few days, an unprecedented coalition of Democrats and Republicans, business leaders and environmentalists formed and collected about one-third of the petition signatures needed to force the referendum. The Board of Supervisors scheduled an emergency session July 23, voting 8 to 0 to let the public decide the issue in November.

Loudoun Democratic Committee Vice Chairman Jim Rocks, a proponent of voter election of the chairman, said the incident illustrated how the county supervisors "never get a chance to get out on the street and talk to the folks." Said Republican County Chairman William Mims, "They were really out of touch on this issue."