MONTPELIER � A Vermont Senate committee appears poised to narrowly approve a bill today calling for instant run-off voting for U.S. Senate and House seats, although the issue proved to be a controversial one during testimony Thursday.

The latest bill calling for a switch to the majority-rule form of electing officials is expected to come down on a party line vote this morning, with three Democrats supporting it and two Republicans voting against it.

But final testimony on the dramatic change in election procedure caused sparks to fly among committee members Thursday morning as Sen. Edward Flanagan, D-Chittenden, accused Sen. William Doyle, R-Washington, of trying to stall a vote.

The accusation came after about 60 minutes of questioning between committee Republicans and Secretary of State Deb Markowitz on the implementation of the proposal. Several other people were also waiting to testify on the bill that day.

Flanagan accused Doyle, who was asking Markowitz a majority of the questions that morning, of engaging in the "fine art of filibustering," a parliamentary procedure often used to delay a vote on a bill.

"I say, let's just do it," said Flanagan, who added that the questions poised by the two Republicans on the body had already been answered through previous testimony, both in the form of witnesses and reports.

Doyle said he resented Flanagan's accusation. The questions he posed to Markowitz were necessary, he said.

"These are legitimate questions that I am asking a witness that any normal person elected to the Legislature would ask," Doyle said.

Sen. Jeanette White, D-Windham, the chair of the committee, vowed that the body would vote on the issue Friday morning, but she did agree that some of the questions asked by Doyle and Sen. George Coppenrath, R-Caledonia, have already been answered.

The committee, which has been periodically reviewing the bill since its introduction early in the legislative session, received last month what can be considered the definitive report on implementing instant runoff voting in Vermont.

The report, prepared by the secretary of state's office and the University of Vermont, detailed how Burlington implemented the system for its mayoral race last year. It also provided cost estimates for implementing the system across the state.

"This report was presented to us with the purpose of informing our decision," White said. "If some of us haven't read that, I can't do anything about it."

The latest version of the instant runoff voting bill focuses just on the state's three congressional seats; previous drafts have included statewide offices such as governor. If signed into law, it would take effect in 2008 � just as Rep. Peter Welch is expected to run for a second term.

Under an IRV system, which is aimed at electing someone with majority support, voters number their preferences for an office.

If a single person does not have a majority of the votes, all but the top two choices are eliminated and "the ballots of voters who chose nonadvancing candidates as their first choices are re-examined so that their votes are counted during the runoff count for whichever of the final candidates is ranked higher on that ballot," according to the text of the bill.

Markowitz, who has endorsed IRV as being fairer than the system now in use, said switching to the system should not increase the length of ballots in non-presidential election years and that a run-off for U.S. House or Senate, if it is needed, would cost about $45,000.

"This [bill] could be effectively implanted by our office," she told the committee.

But Coppenrath and Doyle had many concerns, including whether voters in the state could understand the new system. Both said their concerns with bringing IRV to statewide Vermont races were philosophical and procedural.

"You mentioned voter confusion," said Coppenrath. "Well, I'm confused."

Markowitz responded that a survey following Burlington's successful election last year using IRV found that a majority of residents understood how the system worked. That backed up similar studies in other locations IRV is used, she said.

"I have been convinced by political scientists � that voters can get the difference," she said. "The ballot is self explanatory."

Meanwhile, members of the Vermont Municipal Clerk and Treasurer's Association turned out to oppose the proposal. Alison Kaiser, the chair of the association's legislative council, said the group did not have a consensus on the philosophy behind IRV, but worried that it would end up costing towns.

"We are worried that over time this will cost the towns more money in printing and programming costs," she said. "Especially if some of the local races, such as the justices of the peace, are bumped onto a second ballot page."

Gov. James Douglas expressed similar concerns when asked about IRV during his weekly press conference Thursday. The Republican governor said he worried the system would be confusing to voters and said he was philosophically opposed to it.

"I think elections ought to be actual contests, not just hypothetical ones," he said.