G. Conoly Phillips yesterday joined four other candidates for the Democratic nomination to the U.S. Senate in support of state convention rules that would make it more difficult for front-runner Andrew P. Miller to win the nomination on an early ballot.

Phillips is the born-again Christian whose whirlwind, last minute campaign earned him about 15 percent of the convention delegates chosen at city and county mass meetings on Saturday.

He and the other candidates trailing Miller apparently command the support of a majority of the delegates to the June 9-10 convention in Williamsburg - assuming each will get a share of the uncommitted delegates - and so should have a good chance to revise the proposed rules in a floor vote.

Former state attorney general Miller came out of the Saturday caucuses with a wide lead in delegates, but his opponents believe he will fall at least 200 votes short of the majority needed for nomination on the first ballot.

Miller campaign manager Jim Paxton yesterday attacked the rules change proposals as an effort to prevent delegates committed to candidates out of the running from switching to Miller. He said the changes could lead to a "brokered convention" that might fail to nominate the strongest candidate and lead "to another Democratic defeat in November."

Phillips and the other candidates opposing Miller are objecting to convention rules adopted by a temporary committee that would eliminate candidates who receive 5 percent or less of the vote on the first ballot and those who finish last on subsequent ballots.

They also oppose a rule that the nominee be chosen by a majority of those voting, rather than by a majority of the total delegates to the convention.

The opponents of the existing rules want all eight candidates to remain on the ballot until one wins at least 1,398 votes, a majority of the 4,795 authorized to participate in the convention.

By swinging his bloc of delegates votes behind the rules changes, Phillips yesterday rounded out the potential majority that the trailing candidates hope to muster for a rules fight.The other candidates who have said they favort the changes are state Sen. Clive L.DuVal II of Fairfax County, former Fairfax supervisor Rufus Phillips, state Sen. Hunter B. Andrews of Hampton and former state Del. Carrington Williams of Fairfax.

Two other candidatts, Falls Church feminist Flora Crater and former Fairfax supervisor Federick Babson only have a handful of delegates committed to them and are not considered factors in the rules debates.

Temporary rules committee chairman Raymond Colley of Fairfax said in an interview yesterday that he believes any change should be left to the permanent rules committee of 30 members who will be chosen, three from each congressional district, at the opening session of the Williamsburg convention.

If the permanent rules committee refuses to make the changes, the challenging candidates could force a floor vote on the issue with a petition of only 10 percent of the delegates, a total they could muster easily.

"The state central committee could ask the temporary committee to reconsider the rules," Colley said, "but as far as I am concerned, our work is done and it should be left to the permanent committee. We adopted the rules unanimously after hearing from all candidates and they are ratified unanimously by the steering committee."

Colley said no strong objections were raised against the proposed rules during the adoption process.

The belief is that each of the five trailing Miller has a better chance of getting the nomination if the convention goes through a series of ballots that test the power of each of the candidates to hold his delegates and draw from the others.

With all but 64 of the 2,679 delegates chosen Saturday accounted for state Democratic Party headquarters yesterday reported the following results:

Miller, 989; DuVal, 447; Conoly Phillips, 309; Rufus Phillips, 159; Williams, 83; Andrews 62; Babsib 3; Carter, 1.

The party reported that 541 uncommitted delegates were elected . Proposed rules also permit 116 elected officials - state legislators, members of Congress and Lt. Gov. Charles S. Robb - to vote without making a preconvention commitment to a candidate.