SECOND UPDATE, 12:25 P.M. SATURDAY - The House Revenue Committee just approved a two-year version of Quinn’s tax hike (from the current 3 percent to 4.5 percent flat-rate, to automatically revert back to the 3-percent rate in 2011). It passed on an 8-4 partisan vote. Now goes to the full House, where its future remains uncertain.

UPDATE, 5:36 p.m. FRIDAY - The House just adjourned for the evening without taking any action on any of the items listed below, a fairly stunning development to reporters who were braced for an all-nighter. Lawmakers will return late morning Saturday - meaning they will have less than 48 hours to finish their work. This is going to be widely (and probably correctly) interpreted as a sign that the Democratic House majority doesn’t have the votes it needs to pass Gov. Pat Quinn’s proposed income tax hike, which is the only realistic way that anyone has suggested balancing the budget this year. Stay tuned.

SPRINGFIELD, Ill. – As of late afternoon on Friday, the Illinois Legislature’s list of yet-unfinished business for the year includes:

- Cobbling together a roughly $60 billion annual state budget to keep government operating during the fiscal year that starts July 1;

- Passage of a proposed major income tax hike to address an $11.6 billion deficit in that budget (or, barring that, some yet-unspecified alternative method of dealing with that deficit);

- Reforming the state’s political system with campaign finance limits and other changes demanded by the public in the wake ex-Gov. Rod Blagojevich’s indictment on federal corruption charges;

- Addressing myriad smaller unresolved issues, including whether to allow use of marijuana for medicinal purposes, and whether to approve a controversial tax benefit for a proposed commercial business hub in the Metro East.

They’ve had five months to do all of this. Now they’ve got about 55 hours. They’re suppose to adjourn for the summer by midnight Sunday, and that deadline is real: Under the state’s constitution, any law passed after May 31 can’t go into effect immediately (as the new budget would have to), but must wait until Jan. 1.

The only way around that problem (pay attention – these rules sound like something out of a game of “Dungeons & Dragons’’) is to pass the bills with a “supermajority’’ vote of three-fifths of all legislators, instead of the simple majority that’s needed before that.

That means that, after Sunday, the majority Democratic leaders – who are struggling to find consensus on this stuff even within their own one-party rule – suddenly would also need Republican votes to pass it, which complicates everything. In other words, the state would again be headed for the kind of potential government shut-down that plagued Illinois during much of Blagojevich’s dysfunctional tenure.

That’s not likely to happen. Believe it or not, this down-to-the-wire process is pretty much how it goes even in “normal’’ years. The legislative leaders like to wait until the rank-and-file legislators* are good and nervous about the doomsday deadline before letting them actually see the budget that’s being proposed, so they’ll feel pressure to pass it quickly instead if engaging in pesky debate about it. Our best guess right now is that they’ll drag this into Sunday afternoon and then be home for supper.

[* Rank-and-file legislators in Springfield (your elected representatives) are called ``mushrooms,’’ because they’re kept in the dark and fed . . . manure. This is one of the reasons that political reformers are clamoring to pass a reform package that would actually rein in the power of the handful of legislative leaders who control those legislators by giving them (or withholding from them) unlimited amounts of campaign money. The reform bill that’s likely to pass in the coming hours does give the state its first-ever campaign contribution limits, and includes some meaningful provisions, but almost everyone agrees the bill leaves the power of the leaders mostly untouched. Which is why it’s likely to pass.]