Topeka ? Some Kansas House members are considering an attempt to oust the chamber’s conservative Republican speaker, prompted by the legislative successes of a coalition of Democrats and GOP moderates.

Speaker Mike O’Neal, a Hutchinson Republican, has filed for re-election to the House and expects to return as its top leader next year. Even some critics believe that his support among conservatives means that House Republicans are likely to formally designate him as their choice for speaker for 2011-12.

But the final decision rests with the entire House, and Democrats and moderate Republicans together outnumbered conservative Republicans this year. Democrats and GOP moderates pushed through a tax increase over O’Neal’s opposition and, as the Legislature’s annual session formally ended last week, some House members said the same coalition could remove him from power.

It would be unprecedented for the entire House to reject the majority party’s choice for speaker.

“I think the possibility of a coalition speaker is probably as great as it has ever been,” said House Minority Leader Paul Davis, a Lawrence Democrat.

House members who are talking about ousting O’Neal acknowledge that much depends upon the outcome of this year’s elections, when all 125 House seats are on the ballot. If GOP moderates lose enough seats in the Aug. 3 primary and Democrats lose seats in the Nov. 2 general election, their coalition might not have enough strength to remove O’Neal.

Rep. Scott Schwab, a conservative Olathe Republican, said a move to oust O’Neal will be “a legitimate concern” if enough legislators who voted for the tax increase return.