SPRINGFIELD - A once-unthinkable idea in Illinois, to outlaw campaign contributions from state contractors to politicians, is poised for likely passage in the state Senate today.

"I can't imagine there will be a single vote against it," said the bill's sponsor, Sen. Don Harmon, D-Oak Park, as he left a committee hearing in which the latest version of the long-sought measure was unanimously moved to the Senate floor.

The measure would prohibit entities with more than $50,000 in state contracts from giving political donations to the elected officials who control those contracts.

Senate leaders as late as last week were threatening a rewrite of the bill that could have killed it.

But several sources said Wednesday that threat appeared to be gone, as lawmakers face public pressure to address ethics issues that have racked Illinois lately.

If it passes the Senate today, it then would move on to the House, where the proposal has found strong support in the past. Whether Gov. Rod Blagojevich would sign it into law is an open question, but proponents believe they may be able to pass it by a veto-proof majority. Blagojevich has claimed he wants more reform than the measure provides, which critics say is merely an excuse for him to veto it.

Reformers long have complained that allowing open-ended money to flow from state contractors to the politicians who control their state profits gives the appearance of legalized kickbacks. Attempts to outlaw those contributions have failed for years, however, partly because it would have to get by the very political leaders who benefit from the current system.

Blagojevich alone has raised millions of dollars in campaign funds from state contractors.

"Generally, they don't want to change the system they succeeded in," said Chris Mooney, political scientist at the University of Illinois at Springfield.

This year, many say, pressure is coming from the federal trial of top Blagojevich fundraiser Antoin "Tony" Rezko. Blagojevich hasn't been charged, but the case has cast a shadow over his administration.

The legislation is House Bill 824.

Kevin McDermott can be reached at kmcdermott@post-dispatch.com.