In addition to the 387-page general appropriations bill that designates funding for hundreds of line items, there are the tax code bill (to raise the money) and the fiscal code - as one Democratic aide said, essentially the operator's manual for how a lot of that money gets spent.
"The governor had the general appropriations bill early Friday and he chose not to sign it because he said he was waiting for the whole package to be complete," said Bill Patton, spokesman for House Democratic leader Rep. Frank Dermody (D., Allegheny). "It has now come to light that the package was not complete when he signed general appropriations."
In fact, the tax code and fiscal code bills were still being debated by lawmakers at 11:45 p.m. Saturday when Corbett signed the $27.7 billion general appropriations bill.
Corbett on Tuesday brushed aside the Democrats' contentions as petty, saying he correctly waited until the fiscal and tax codes had passed the legislature.
"They did not get signed [before the deadline] but they were voted upon and that was enough," he told reporters.
Senate Majority Leader Dominic Pileggi (R., Delaware) said the budget is the appropriations bill.
"I have no doubt the budget was timely signed," said Pileggi, adding that lawyers "can have a nice debate" on it if they want.
Patton, the House Democrats' spokesman, said since the Republicans were crowing about the budget passing on time, it seemed worth pointing out the missing bills.
"Maybe they need to eat a little crow," said Patton.
Seasoned budget watchers may recall the eight-year run of unmet deadlines under then-Gov. Ed Rendell, though he maintains he met the deadline in 2003 - except for education funding, which didn't get approved until December of that year.
What did Corbett's procrastinating predecessor have to say of Saturday night's events?
"They didn't do it, they broke the pledge," said Rendell, feigning indignation. "No, the answer is, it's an artificial deadline. It's silly and has no consequence to citizens."
In fact, the former governor said, missed deadlines can lead to legislative victories. "Some of the best things I got done were because I didn't sign the budget on time," he said. Rendell did not mention his most famous blown deadline: the 101-day budget impasse of 2009.
And if the budget deadline is missed by a few hours or days? Not the end of the world, said Cheri Freeh, outgoing president of the Pennsylvania Institute of Certified Public Accountants.
"Technically a budget is a guideline on expenditures, but I tend to agree that you need the pieces in order to make it work moving forward," said Freeh, of Quakertown. "But it's always nice to have a budget passed on time."
Contact Amy Worden at 717-783-2584 or firstname.lastname@example.org or follow on Twitter @inkyamy.