CHICAGO (CBS) — A Cook County judge will hear arguments next month on a lawsuit challenging Gov. Pat Quinn’s veto of legislative salaries.

WBBM Newsradio’s John Cody reports the governor attended a hearing on the lawsuit Tuesday morning at the Daley Center, and stressed the importance of resolving the state’s $1 billion pension crisis.

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Quinn used his veto powers last month to block lawmakers’ pay, after they failed to reach an agreement on pension reform by a July 9 deadline he had set.

House Speaker Michael Madigan and Senate President John Cullerton have sued to force Quinn and Illinois State Comptroller Judy Baar Topinka to issue lawmakers’ paychecks.

“This is going to be a landmark case. It involves the Illinois Constitution, and the rights of the governor to line-item veto the appropriation of the legislative salaries until the pension reform is done for the people,” Quinn said.

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The lawsuit filed by Madigan and Cullerton asks a judge to determine if Quinn’s veto really did eliminate lawmakers’ salaries, and if so, to declare the move unconstitutional. If his veto did not eliminate their salaries, the lawsuit argues Topinka’s office should be ordered to pay lawmakers’ salaries.

Madigan and Cullerton have said Quinn’s move was “an unconstitutional attempt to coerce the Legislature to comply with his demands.”

Topinka has said she has no choice but to withhold lawmakers’ paychecks.

Illinois Attorney General Lisa Madigan’s office will represent Topinka in the case, even though her father is one of the plaintiffs in the suit. Her office said there is no conflict of interest over her relationship to the speaker, since he filed the lawsuit in his official capacity as a legislative leader.

Cook County Judge Neil Cohen will hear arguments from both sides on Sept. 18, after attorneys submit written briefs.

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A bipartisan conference committee – composed of five state representatives and five state senators – has been meeting for weeks in an effort to reach a compromise on pension reform.