A proposal that would have let the planned development of Reston form its own town government was defeated by an almost 2-to-1 margin yesterday, in a vote the measure's supporters attributed to a growing national distrust of government.

"This seems to be a big antigovernment vote tonight," said Reston attorney John Morris, a leader of the forces who have agitated for Reston self-determination almost since the "new town" sprung from a Fairfax County cow pasture 15 years ago. "People are just saying they don't want any additional government."

The closest question on the statewide ballot in Virginia yesterday proved to be a proposed constitutional amendment to allow the state legislature to hold a special session each year to act on legislation vetoed after adjournment of the regular session. But with 84 percent of the vote counted, the measure was approved, 59-41 percent.

A controversial Fairfax County proposal to expand and renovate the two-year-old county jail was defeated by a margin of six percentage points. Final unofficial returns showed the $8.55 million bond measure defeated by a vote of 96,016 to 85,265, although four other county bond referenda totaling $54.45 million were approved by wide margins.

Voters easily approved three other proposed amendments to the state constitution, which were aimed at further limiting localities' indebtedness and giving them the right to grant new kinds of tax exemptions. An Arlington proposal to allocate $6 million for improving water supply lines was leading by a margin of more than 6 to 1.

Economic arguments dominated the debate over the veto session proposal, which was supported by virtually all of Virginia's largely Democratic state legislature, but was opposed by Republican Gov. John Dalton and the Taxpayers Alliance, a conservative citizen's lobby.

Dalton had painted the proposal as a boondoggle that could cost state taxpayers between $55,000 and $150,000 a year. He had argued that legislators could avoid the problem of last-minute vetoes if they would only speed up their work, allowing him to veto bills before they went home for the year.

The legislative leadership, backed by the League of Women Voters, Common Cause, the NAACP and a host of other interest groups, had argued that the measure would ensure that the state government's executive and legislative branches were on an even footing.

Economic questions also were a major factor in the debate over the Reston proposal, which would have given the community of 35,000 the right to elect its own mayor and council.

The proposal was caught between residents who said it would give the area too much government and others who said it would not give it enough.