By Brendan O'Brien
MADISON, Wisconsin (Reuters) - Four more Wisconsin Republican state senators, including the Senate leader, will face recall elections this year, bringing the number of state lawmakers forced to campaign in special elections to 40 percent of the entire Senate, officials said.
The state agency that oversees elections agreed unanimously on Monday that enough valid signatures by voters were submitted to require all four senators to face recall votes.
The four lawmakers include Senate President Scott Fitzgerald, a chief architect of an anti-union law passed last year that sparked the recall movement.
The date of the votes has not yet been set.
The decision means 13 of the state's 33 senators will have already faced a recall vote or will soon face one since Republican Governor Scott Walker pushed an anti-union law through the legislature last March.
Nine state senators faced recall last summer, six Republicans and three Democrats. Two of the Republicans were defeated, leaving the Republicans with a thin 17 to 16 majority in the chamber. The Democrats were challenged because they opposed the union law.
The law championed by Walker stripped unions representing teachers and other state and local government workers of much bargaining power over wages and benefits. It also required public workers to pay more for health insurance and pensions. Republicans said it was needed to restore the financial health of the state.
Outraged union supporters and Democrats vowed to vote the Republicans out of office. They have collected more than one million signatures to recall Walker. They also submitted a recall petition against his lieutenant governor.
The dates for the Senate recall elections have not yet been set in part because the election agency has not completed reviewing the huge volume of signatures seeking Walker's ouster.
The recall movement in Wisconsin has created a toxic partisanship in the state, likely to be a battleground in the 2012 presidential election.
Wisconsin voted for President Barack Obama, a Democrat, in 2008 but then elected Walker and Republican majorities of the legislature in 2010, and ousted a longtime Democratic U.S. senator.
Polls have shown a close vote in any Walker recall vote. If the signatures are verified, Democrats will still have to pick a candidate to face him. So far the best-known Democratic candidate to announce a run for governor is Douglas La Follette, a relative of well-known Wisconsin progressive "Fighting Bob" La Follette who once served at governor and U.S. senator.
(Writing by Greg McCune; Editing by Paul Thomasch and Will Dunham)