SPRINGFIELD, Ill. • Less than 24 hours after carving out exceptions to the Illinois' new corporate income tax hike under threat that Sears would yank its corporate headquarters from the state, lawmakers in both parties are trying to roll back the whole tax statewide.

House Republicans this morning conducted a statehouse news conference to unveil their plan, which would take the current 7 percent corporate tax back to its old rate of 4.8 percent over the next few years. That's on the heels of legislation filed Tuesday by a group of House Democrats that would take it back to the old 4.8 percent rate all at once, as of January 2012.

"The approach we have is not working . . . doing it one business at a time," House Minority Leader Tom Cross, R-Oswego, told reporters this morning.

Lawmakers earlier this week passed a measure to provide special tax breaks to Sears and the Chicago Mercantile Exchange after the companies threatened to leave the state because of the new tax structure imposed this year.

Republicans especially are taking a told-you-so approach to the issue, pointing out that Democratic support of the Sears legislation was an admission that the tax hike the Democrats pushed through last year was a job-killer.

This week's $300-million-a-year, two-bill tax-relief package was primed with other incentives to get hesitant legislators on board, including a $50 increase in the current $2,000-per-person standard exemption, a higher earned-income-tax credit for the working poor, a reduction in the state's estate tax, and tax relief for a smaller company in southeastern Illinois.

Even at that, the measures drew fire from anti-Wall Street protestors who unfurled a banner during House floor debate Monday alleging "corporate extortion." Some conservatives also blasted the deal for favoring a few companies over others.

Still, an across-the-board corporate-tax rollback would run into some serious political problems. Individuals in Illinois pay a flat-rate 5 percent income tax under the new tax hike, meaning a mass rollback of corporate taxes would have those corporations paying a lower rate than an average family does -- not a popular dynamic today. Neither of the new rollback bills does it for individuals, or for small companies that usually don't use the corporate tax structure.

Also, Cross acknowledged that dropping the corporate tax will cost the cash-strapped state about $400 million per point that it drops. "Sure, it means (budget) cuts," he told reporters.

Democratic Gov. Pat Quinn pushed the new tax hike into law last year, saying it was necessary to keep basic state services in place in light of a record budget deficit. However, Quinn also backed the exceptions passed by the Legislature this week, saying the loss of 6,000-plus jobs from a Sears pullout would hurt worse than the loss of tax revenue. (We've got a call in to Quinn's office regarding the latest proposals.)

The Democratic rollback bill is HB3917. The Republican one is HB3918.