SPRINGFIELD - Illinois' political reform movement, pushing for years against a stubbornly unreformed system, is one signature away from its biggest victory: a law to end a prevalent form of campaign donating that some say looks an awful lot like bribery.

The problem is that one signature has to come from Gov. Rod Blagojevich, whose campaign fund has benefited from the very practice that would be outlawed. He has let the legislation sit on his desk for a month now, while hinting he might alter it with an amendatory veto that many believe could effectively kill it.

"It will be like throwing gasoline on a fire," warns Cynthia Canary, a reform lobbyist who views the legislation as a make-or-break moment for political ethics in Illinois.

At issue is a bill passed by the legislature earlier this year to ban so-called "pay-to-play" political donations from state contractors. It would make it illegal for any entity that holds $50,000 or more in state contracts to give political donations to the elected official who controls those contracts.

Blagojevich has said he might toughen the bill by adding

provisions through an amendatory veto, including donation limits on all contributors.

"The governor's looking at ways to make it stronger," said Blagojevich spokesman Lucio Guerrero. "We don't know when this (chance) will come around again. If we're only going to get one bite of the apple, we want to make it a great bite."

The problem is, an amendatory veto would send the bill back to the legislature, where it took several years of negotiations to get it passed the first time. If lawmakers don't approve the bill with the new language written in, it wouldn't become law, which many skeptics allege is exactly what Blagojevich is hoping for.

"The governor is going to do whatever he can to derail this," said state Rep. John Fritchey, D-Chicago, co-sponsor of the bill, which passed both houses unanimously. "He's had six years to pursue an independent agenda on ethics, and he's done nothing other than try to hamper it."

Blagojevich formally received the bill June 30. Under the state constitution, he must sign, veto or amend the bill within 60 days of that date, or it automatically becomes law. That would make Aug. 29 the deadline for action.

If Blagojevich amends the bill, the legislature could accept his changes with a simple majority vote or override him with a three-fifths vote to put the original bill into law.

Negotiations earlier this year included an unusual agreement among key lawmakers that they will mobilize enough support in both the House and Senate to override any veto. While that's certainly not a guarantee, it may give Blagojevich pause and could be part of the reason he hasn't yet done anything with the bill.

Guerrero, Blagojevich's spokesman, pointed out that the law wouldn't go into effect until Jan. 1 in any case, so there's no urgency to signing it prior to the constitutional deadline.

Blagojevich last week hinted that he might sign the bill, if that's what it takes to get legislative approval for his proposed statewide infrastructure rebuilding plan. House leaders have refused to fund the pared-down $25 billion plan, in part because many of them don't trust Blagojevich's office to fairly administer that kind of spending.

During a meeting in Chicago recently with top lawmakers about the infrastructure plan, Blagojevich talked of the possibility of signing the ethics bill.

State Rep. Barbara Flynn Currie, D-Chicago, a top House official who was in on the talks, said last week that such a move might soften some opposition to the plan, but she stopped short of agreeing to it.

"One of the concerns is whether the governor is looking for a capital plan as a way of rewarding his friends," she said. "Whether (signing the ethics bill) is enough to solve the problem of trust, I don't know, but it's a good first step."

The issue of political contributions from state contractors has long been a controversial one in Illinois, but there are no rules against it, as long as the donations aren't made specifically as payback for the contracts.

Former Gov. George Ryan is serving a federal prison term for crossing that line. His crimes included steering state contracts to major campaign contributors.

This year's federal trial of Blagojevich fundraiser Antoin "Tony" Rezko included allegations of similar things going on around Blagojevich's administration. Testimony alleged that Blagojevich associates sought a political donation from a contractor in exchange for a promise of state business. Blagojevich hasn't been accused of wrongdoing.

A recent St. Louis Post-Dispatch review of about 50 of the top service contractors in the state found that fully half of them are major Blagojevich donors.

kmcdermott@post-dispatch.com