BY FAILING TO reach agreement on a major spending bill before the winter break, legislative leaders have squandered much of their control over what goes into it, and they have courted more federal scrutiny of the state’s election process.

In the wee hours of early Thursday morning, the House and Senate essentially threw in the towel, gaveling out their last formal sessions until January without enacting a bill that would divvy up the roughly $1 billion surplus from 2019, approve some union contracts, close the books on the fiscal year, and establish September 1 as the date of next year’s state primary. October 31 was the deadline for the state comptroller to file an annual financial statement based on a signed version of the closeout budget bill.

Secretary of State William Galvin says the enduring uncertainty could create problems with the Federal Voting Assistance Program, which sometimes sues states to ensure there is enough time between the primary and a general election to deliver ballots to members of the military and other voters living overseas.

The House and Senate have both agreed on a September 1 primary election, which Galvin said would grant ample time, but that has not yet been set into law, which has created some concern within the federal bureaucracy.

“Historically, they haven’t been that flexible,” Galvin said in a phone interview.

The closeout budget bill also includes the funding and authorization to, for the first time, offer five days of early voting ahead of the March 3 presidential primary, where Galvin anticipates at least a couple million people turning out around the state. The state’s top elections officer suggested that passage by January 15 would be too late to give local clerks the green light to move forward with early voting plans, but he wouldn’t estimate the latest point when he could do that.

Galvin said he might ask the governor to file a separate bill that deals exclusively with the urgent election issues that he believes are non-controversial so that they could be extracted from the tangle of the closeout budget bill.

It’s unclear what precisely prevented the closeout budget bill from passing. There appeared to be a last-dash effort to push something through in the final hours of the final formal session of the year. In addition to policy disagreements, the House and Senate had for weeks been at loggerheads over which piece of legislative paper should be used to pass the bill. On Wednesday night, the Senate conceded on that front, and both branches appointed a six-member conference committee to try to work out the policy differences.

Senate Ways and Means Chairman Michael Rodrigues and House Ways and Means Chairman Aaron Michlewitz led negotiations for each chamber. The conference committee met briefly in Rodrigues’s office on Wednesday night, but they didn’t strike a deal. While the House floor was mostly quiet except for members’ private conversations on Wednesday night, the Senate had a full plate in its final session of the year, debating and passing a bill to ban flavored tobacco products and a bill to ban plastic bags.

Once time ran out early Thursday morning, House Speaker Robert DeLeo issued a statement saying the House was eager to strike a deal, while Senate President Karen Spilka indicated her branch had offered some compromises without getting takers in the House.

Moving forward, the House and Senate will have limited flexibililty. There are no more formal legislative sessions allowed until January, which means that, if House and Senate leaders agree on a compromise version of the fiscal 2019 closeout budget bill, any lawmaker who is determined enough to make a stand, could block the bill from passage. In so-called informal sessions, a single lawmaker can put off action on legislation.

Some have speculated that progressive House members who objected to a corporate tax break included in the House version of the bill might exercise their rights to block a bill that retains the tax break because they were outspoken opponents of that proposal before. That dynamic might give the Senate more leverage because top senators don’t want the tax provision included in the must-pass bill. That was one of the big differences between the two bills, which have yet to be reconciled.

But the dynamic could work in the other direction as well. The more tax-averse Republican minority members view the House provision not as a tax break, but as a way to avoid a tax hike that was included in the 2017 federal tax law, which overall reduced business’s tax burdens. House Minority Leader Brad Jones declined to discuss whether House Republicans might hypothetically block a closeout budget bill from passage if they don’t like what is in it. But minutes after the House gaveled out from its last formal session of the year early Thursday morning, Billerica Republican Rep. Marc Lombardo said that the power to throw up roadblocks if the tax provision is left out would be “something to consider” in the remaining informal sessions leading up to December 31.

There’s another harder deadline that appears to be hanging over lawmakers’ heads. Spending bills like the closeout budget “cease to exist” at the end of the calendar year, according to the joint rules. That means that if lawmakers send Gov. Charlie Baker a bill before January, he would be able to strip items out of it without giving the House or Senate any recourse to put them back in.

The governor has line-item veto authority on spending bills, meaning he can zero-out portions of a spending bill while signing the rest of it into law. If the Republican governor wanted to eliminate certain earmarks or other aspects of the bill, lawmakers would have no opportunity to override those decisions.

Baker can be indulgent in tolerating lawmakers’ appetite for spending. This year he signed into law the entirety of the fiscal 2020 budget, earmarks and all, and DeLeo said he anticipates that the governor would at least sign the bulk of anything they send his way.

“I’m uncertain in terms of what the governor would veto or not veto, but I feel fairly optimistic that for the most part it would be accepted by the governor,” DeLeo said. “That may not be as big an issue as it could be.”

Jones anticipated that he and the governor will probably take similar views on the spending legislation, and he envisioned what might happen as the governor has free rein to make cuts.

“They’ve basically given him veto power,” Jones said. “The Twittersphere will go crazy with how outrageous it is, when the reality is, if any member has that problem, they should look at the speaker and Senate president and say, ‘You gave this authority. Remember, you could have gotten this bill done weeks, months ago.’”