Late Tuesday night, congressional negotiators unveiled a spending deal to keep most of the government funded through September 2015, but on Wednesday it became clear that the substantial policy concessions made by Democrats in a bid to attract enough Republican votes to keep the government open are likely to shrink the coalition supporting the last-minute bill.

The 1,600-page spending document could be forced through the House and Senate in less than one week, giving lawmakers little time to review its contents but enough time to be angered that certain controversial provisions were included, most notably major changes to two of the biggest laws approved by Congress since 2000, which had rewritten Wall Street rules and reformed the campaign finance system.

The current government spending bill expires on Thursday, and failure to pass new legislation by then will trigger another shutdown a little more than a year after Republicans forced a 16-day government closure in October 2013. That GOP standoff over defunding the Democrats’ health care law cost the nation an estimated $24 billion.

Though the so-called cromnibus bill funds the majority of the government through an omnibus package for the rest of the fiscal year, it pays for the Department of Homeland Security only through February via a stopgap measure known as a continuing resolution, or CR. Conservatives hope to isolate the department, which is tasked with implementing President Barack Obama’s recent executive order exempting millions of undocumented immigrants from deportation, and the bill will give Republicans a chance to freshly debate its funding in the new year, when they will control both the House and Senate.

Yahoo News’ list of the most interesting and significant policy changes in the year-end spending bill:

Eliminating a key Wall Street reform. The Democratic-controlled Congress in 2010 approved sweeping changes to the nation’s financial systems, many of them tailored to prevent the kind of crisis that tanked the economy in 2008. One of the centerpieces of the bill was a measure designed to spin off banks’ riskiest activities into subsidiaries, isolating the main functions of banks from those risks and also ensuring that taxpayers would not be on the hook to pay for losses created by those risky trades in the event that they failed. The spending bill approved by Congress eliminates the so-called push-out provision from the Dodd-Frank law, meaning that the trading of derivatives — the risky swaps or bets made against the rise and fall of value in assets — can now once again happen in-house in Wall Street’s largest banks.

Democrats led by Massachusetts Sen. Elizabeth Warren are outraged by this return to old ways, and she has said she will oppose the whole bill if the provision remains in it.

Dismantling what was left of campaign finance reform. The Supreme Court since 2010 has repeatedly struck down political donation restrictions approved by Congress in the 2002 McCain-Feingold campaign finance law. With the spending bill approved by Congress this week, lawmakers at the last minute agreed to undo the most significant remaining changes from the law: the limits for individuals on how much they can give to political parties. Before the change, which was inserted in the last few pages of the mammoth spending bill, the most any one person could give to a party group like the Democratic National Committee or Republican National Committee was $32,400 per year. Now any individual will be able to give anywhere from $97,200 to $777,600, depending on the interpretation of the language included in the government-spending bill.

Meddling in D.C. politics. Because the District of Columbia is not a state, it relies on Congress annually to appropriate its budget. And so Washington, D.C., perennially bears the brunt of congressional compromises as Republicans target D.C. programs to highlight social issues they oppose and Democrats acquiesce in the knowledge that the District will vote overwhelmingly for Democrats no matter what Congress does. During the first shutdown threat of Obama’s tenure in 2011, the GOP pushed through a ban on funds for abortion services in D.C. and started a school voucher program.

This year, Democrats agreed to support Republican language targeting a D.C. ballot initiative legalizing recreational marijuana, which voters approved by nearly 70 percent in November. The wide-ranging appropriations bill bars funds from being used for the implementation, regulation and taxation of marijuana and also, adding insult to injury, mandates that no money provided by Congress can be used by D.C. officials to petition for representation in Congress. Instead of a regular congressperson, D.C. has a delegate, Democrat Eleanor Holmes Norton, who does not have voting privileges in the House.

Cutting IRS and EPA funding. Republicans are touting cuts to the budgets of the Internal Revenue Service and the Environmental Protection Agency. The spending deal reduces IRS spending by $345 million in an olive branch to conservatives still miffed over a scandal involving the agency and its targeting of political groups that were using nonprofit loopholes to avoid paying certain taxes. The IRS funding levels in 2015 will now be lower than they were in the 2008 fiscal year.

Republicans have cut the EPA’s budget for the fifth consecutive year. In a press release the day after the deal was announced, Speaker John Boehner, R-Ohio, touted cuts to the EPA as one of the “Ten Things You Should Know About the Omnibus Appropriations Bill” and the fact that the bill reduces EPA staffing “to the lowest level since 1989.”

Setting up a messy immigration funding fight. A key feature of the deal for Republicans is that it funds most of the government while specifically preventing Congress from filling the Homeland Security department’s coffers. That particular bargain will allow the House and Senate GOP majority in 2015 to fight over how to appropriate overall Homeland Security programs while withholding funds for the implementation of the president’s immigration executive order. As Yahoo News previously reported, it will be difficult for the GOP to defund implementation of the order because the DHS agency that oversees immigration status changes is self-funded through fees it levies on immigration applications. And yet by agreeing to this particular deal, Democrats are setting themselves up for a messy fight with Republicans about the immigration issue at a time when they will have much less leverage to get their way.

Rolling back truck safety regulations. A policy rider added to the bill to sweeten the deal for Republicans will roll back truck safety regulations issued by the Department of Transportation in 2011 to prevent traffic accidents resulting from trucker fatigue. The two basic requirements were that drivers take a 30-minute rest break within the first eight hours of their shifts and take a “restart” period of 34 hours of rest weekly. According to the Department of Transportation, the “net effect of these changes was to reduce the average maximum week a driver could work from 82 hours to 70 hours.” Trucking companies have been lobbying against these changes and now appear to have secured a victory by getting their repeal included in the spending bill.