AUGUSTA – Democrats have effectively held control of the Maine House of Representatives for three decades, and as a new session opened this week they continued to cling to power – barely.

Opening day featured an improbable turn of events, with a final resolution still in the offing.

Convening on Wednesday, the 151-seat chamber was knotted, 73-73, between Democrats and Republicans, thanks to the latest in a series of unenrollments by Democratic members that increased the number of independent representatives to four. There also is a Green party member.

The numerical tie prompted Republicans to push for adjustments in committee assignments and partisan staffing.

Speaker John Richardson, D-Brunswick, was ready to agree to give the GOP half of the chairmanships, but at the last minute, Rep. Joanne Twomey of Biddeford, who recently declared herself an independent, announced she was re-enrolling as a Democrat.

An outspoken liberal, Twomey suggested she had a responsibility to keep her original party at the helm of the House despite her dissatisfaction on budget issues and other matters.

“Oh, talk about drama!” she told her colleagues before laying out her reasoning and declaring there were no deals involved in her change of heart.

“This is my decision, however it plays out back home. ‘Boy, this girl is indecisive. One day she is this, one day she’s …’ I haven’t changed my ideals,” Twomey said in an emotional floor speech.

With a new 74-73 plurality, the Democrats scrubbed the power-sharing plan – at least for now.

House Republican leader David Bowles of Sanford said his caucus would still pursue “parity” and Richardson said leading lawmakers would talk. Barring a new defection, major organizational changes appear unlikely.

But there still could be Democratic concessions on staffing and on overall representation on committees.

The major political parties compete energetically against each other in Maine, where voters elected independent governors in the late 1970s and in the 1990s.

Ten years ago, a deadlocked House divided committee chairmanships evenly. Since then, the state Senate experienced full power-sharing for a term in which a Democrat served as president in 2001 and a Republican presided in 2002.

Currently, Democrats hold the Senate with a 19-16 edge. The margin was a bare 18-17 coming out of the November 2004 elections, but a party switch widened the gap.

The Legislature has 17 regular committees with 13 members each, 10 from the House, three from the Senate. Democrats hold numerical superiority among House members on eight of the panels, according to a House tabulation, while seven are evenly divided and two have more House Republicans than House Democrats.

Overall, House Democrats fill a total of 89 committee slots, compared to 77 for Republicans, according to the House compilation.