Topeka ? Big changes are in store for the Kansas Senate, with the balance of power among Democrats, centrist Republicans and right-of-center Republicans in doubt until this year’s elections.

The chamber’s top two Republican leaders, President Dave Kerr and Majority Leader Lana Oleen, are not seeking re-election.

At least five of their colleagues in the 40-member chamber also are bowing out, and redistricting forced two incumbents into a single district.

Democrats hope to reduce Republicans’ 30-seat majority and make it easier for Democratic Gov. Kathleen Sebelius to win passage of legislative initiatives.

Republicans who want to prevent tax increases, shrink government and pursue a conservative social agenda hope to gain enough clout in the Republican caucus to govern the chamber.

The results of this year’s elections will affect how the Senate deals with numerous issues, ranging from education funding to a proposed constitutional ban on gay marriage.

“After these elections, the Senate is going to be a much different place,” said Minority Leader Anthony Hensley, D-Topeka.

All 40 Senate seats will be filled in this year’s election as well as all 125 Kansas House seats. The candidate filing deadline is noon June 10.

Retiring, redistricting

Besides Kerr, R-Hutchinson, and Oleen, R-Manhattan, four other Republicans have announced they will not run again. They are Bill Bunten of Topeka, Bob Lyon of Winchester, Ed Pugh of Wamego and Robert Tyson of Parker. Another Republican, Stan Clark of Oakley, was killed in a traffic accident Saturday.

One Democrat, Christine Downey of Newton, also has announced plans to retire.

Redistricting in 2002 put Sens. Larry Salmans, R-Hanston, and Janis Lee, D-Kensington, in the same district. The rewriting of district lines also created a seat in Johnson County with no incumbent.

Thus, the 2005 session will begin with at least nine new faces and the election loss of at least one incumbent. Kansas voters could retire other senators involuntarily as well.

“It’s far too early to predict what the changes will be,” said Sen. John Vratil, R-Leawood, the chamber’s vice president. “I think we’re going to have 10 to 12 new senators.”

GOP dominance

Republicans are almost certain to retain their majority, given their current dominance. The only time Democrats have captured a majority was 1912, when a split between conservatives and Bull Moose progressives in the GOP also helped elect Democrat Woodrow Wilson.

Hensley said Democrats could realistically hope to win 14 or 15 seats, enough, he said, to regularly forge coalitions with dissident Republicans and help Sebelius achieve her policy goals.

“We certainly would leave a much larger imprint on things,” he said.

Open seats typically represent the best opportunities for gains by Democrats or the wing of the GOP that doesn’t hold a district. For example, Hensley said, Democrats would not have a shot at Oleen’s seat were she running again.

Losing seats would drop Democrats into single digits in the Senate for the first time since 1972, when the partisan split was 32-8 in the GOP’s favor. Vratil said 32 seats probably represented the outer limit of his party’s possible dominance.

Hensley said much would depend on his and other Democrats’ efforts at recruiting strong candidates.

Hoping for gains

Conservative Republicans are hoping for gains, too. After the November general election, GOP senators and senators-elect will meet to pick a new president and majority leader.

The chamber’s most conservative senators did not consider Kerr one of them, though he sometimes voted with them. Oleen supported raising taxes to benefit schools and was a strong supporter of abortion rights as well.

Clark said in an interview Friday, before his death in a weekend traffic accident, that his fellow conservatives hoped not only to fill leadership positions but also to pick up votes regularly from a few Democrats who were more conservative than their leaders.

“Conservatives have a good chance of gaining a few seats,” Clark said. “The challenge is to govern.”