A swath of sticky policy debates could entangle an upcoming final spending package for fiscal 2018, as lawmakers aim to attach their pet policy “riders” to the must-pass bill.

Negotiators are aiming to complete work on the massive $1.2 trillion bill and pass it before March 23, when the fifth stopgap funding measure of the fiscal year, which began Oct. 1, expires. Before they do, they’ll need a deal on which policy issues, from guns and immigration to Russia’s election meddling, will ride alongside the spending package.

Here are 10 topics that could bog down the spending talks.

Immigration

The omnibus is the next opportunity for lawmakers pushing to extend protections for about 700,000 young undocumented immigrants who are shielded from deportation by the Obama administration’s Deferred Action for Childhood Arrivals program, or DACA.

The Senate last month stymied competing versions of an immigration and border security deal. Some senators want to take another shot when the omnibus comes up — potentially just a short-term extension of the DACA protections. And lawmakers on both sides have previously said they won’t support any spending bills that don’t include a DACA fix.

[Spotlight on House After Senate Failure to Pass DACA Fix]

President Donald Trump has moved to unwind the program starting March 5, but that executive action is on hold likely for months as federal courts consider the matter.

Besides the DACA debate, other immigration-related riders are likely to stoke a fight. Those might include Democratic proposals to prohibit government use of private immigrant detention facilities or restrict funding for Trump’s U.S.-Mexico border wall, and Republican efforts to ban so-called sanctuary cities or force the U.S. Census Bureau to inquire about citizenship status.

Watch: Trump’s Impulsiveness Could Get in Way of Border Wall Promise

Gun control

The Valentine’s Day shooting in Parkland, Florida, has reignited the gun debate in Congress, a partisan fight that has entangled appropriations work in the past.

Several groups of lawmakers are now seeking various gun law changes, from bolstering enforcement of background checks to banning assault weapons. Pushing any proposal through the House and Senate remains a long shot. If no action is taken in the next week or two, many lawmakers, especially Democrats, will be eyeing the omnibus as their best chance to force a gun debate.

It wouldn’t be the first time. House Minority Leader Nancy Pelosi has demanded gun law changes as part of previous omnibus spending bills, to no avail.

And Democrats in both chambers are again calling for a repeal of the so-called Dickey amendment, a long-standing provision in appropriations that effectively blocks the Centers for Disease Control and Prevention from studying gun violence as a public health issue. Attempts to remove the language, named for former Rep. Jay Dickey, an Arkansas Republican, have been rejected year after year.

Watch: Pelosi Says Country Needs ‘Substantial’ Gun-Control Bill

Planned Parenthood

Another perennial spending fight revolves around the women’s health group Planned Parenthood, a longtime target of anti-abortion lawmakers.

GOP language to block federal funds for the group was included in a House-passed fiscal 2018 appropriations package, but not in the Senate’s Labor-HHS-Education spending bill. House Republicans have typically lost similar standoffs in the past.

Last year’s fiscal 2017 appropriations package — enacted under GOP control of Congress and the White House — did not include a provision defunding Planned Parenthood, to the disappointment of many conservatives. Republican leaders instead wanted to target the organization through repeal of the 2010 health care law.

After the repeal effort fell flat, abortion opponents again set their sights on spending bills to defund Planned Parenthood. That means one of the most explosive social issues could come roaring back this month.

If so, the political stakes could be high. It was an internal Republican fight over Planned Parenthood in 2015 that led to the surprise resignation of then-Speaker John A. Boehner.

Russian meddling

Democratic leaders and top appropriators are calling for an extra $300 million in the omnibus for the FBI to combat Russian interference in the upcoming midterm elections. Besides asking for extra money, lawmakers have also drafted proposals to confront Russia and to shield special counsel Robert S. Mueller III’s investigation into the 2016 election meddling.

For example, Rep. Nita M. Lowey of New York, the top Democrat on Appropriations, filed an amendment last year to prohibit the Justice Department from using funds to “obstruct” Mueller’s investigation. Other House Democrats pushed similar plans. On the other side, Republican Rep. Ron DeSantis of Florida had an amendment last year to wind down Mueller’s investigation after 180 days.

Similar proposals could arise this month, though congressional leaders are likely to steer clear of the more provocative ideas.

The omnibus is also a chance for two Senate appropriators, Republican Marco Rubio of Florida and Democrat Chris Van Hollen of Maryland, to push their own measure to deter Russia from future election interference.

Watch: Intelligence Officials Aware of Russian Activity Aimed at 2018 Elections

Environmental protections

Republicans for years have loaded up spending bills for the EPA and Interior Department with policy riders that would roll back Obama administration environmental rules, though the most controversial were often not signed into law. Those riders are again on the table as lawmakers write the new omnibus.

House appropriators included controversial GOP provisions in their fiscal 2018 Interior-Environment bill, while senators have taken a more bipartisan approach. One House-passed rider would make it easier for the Trump administration to end former President Barack Obama’s clean water rule, which expanded federal authority over waterways. Another would stop the government from regulating lead content in certain ammunition and fishing tackle.

Protections for threatened species, like the greater sage-grouse, have also prompted fights between Democrats and Western Republicans.

Senate appropriators on both sides appear determined to brush back many of the House-approved riders.

Trump properties

Democrats last year filed a slate of appropriations amendments aimed directly at the president.

Many would have barred the government from spending taxpayer funds at Trump properties or entering into contracts with Trump-owned businesses. Others sought to pressure the president to release his tax returns or even to prohibit funding to pay the salaries of specific Trump advisers.

Democrats are sure to revive some of those proposals this month, though it’s unlikely they’ll gain any foothold in the spending measure.

Campaign finance

Several Republican-backed provisions to ease campaign finance rules will again be on the table, including one that was stripped at the last minute from their landmark tax code overhaul.

That provision would have allowed churches to engage in political activity without losing tax-exempt status. The language is part of the fiscal 2018 spending plan the House passed in September.

Other riders in the House package would block a new Securities and Exchange Commission rule requiring public corporations to disclose political contributions to shareholders and continue an existing law barring the use of funds to force federal contractors to disclose political spending. House Democrats last year tried unsuccessfully to strip those provisions from the bill.

Meanwhile, the Senate’s draft Financial Services spending bill includes a campaign finance rider backed by Majority Leader Mitch McConnell but opposed by a mix of Democrats and conservative Republicans. The provision would loosen restrictions on coordinated spending between political candidates and parties.

Tax fixes

GOP tax writers are also looking to the omnibus as a vehicle for several fixes to the new tax law.

A number of flaws in the new tax code have become clear since Republicans enacted their landmark overhaul in December. One glitch appears to allow hedge fund managers to skirt certain rules on carried interest profits by setting up limited liability companies and converting to S corporations, which inadvertently were not subjected to the new requirements in the tax law.

Another flaw has grain dealers grousing that they’re now at a competitive disadvantage to agricultural cooperatives, thanks to a provision in the tax law known as Sec. 199A that allows grain farmers to deduct up to 20 percent of their total sales to co-ops but not independent grain companies.

House Ways and Means Chairman Kevin Brady of Texas said it’s “likely” that technical corrections will be part of the omnibus. But that will require cooperation from Democrats, who unanimously opposed the new tax law and aren’t eager to help Republicans fix their signature legislation.

Health care changes

Measures to bolster federal and state health care exchanges could also be included.

A bipartisan health care plan from Republican Sen. Lamar Alexander of Tennessee and Democratic Sen. Patty Murray of Washington is still being discussed with an eye towards the omnibus as a vehicle. The legislation could include cost-sharing subsidy payments or funds for new state reinsurance programs.

Puerto Rico aid

The island territory wrecked by Hurricane Maria last year is now having trouble getting the financial assistance it was promised by the U.S. government, according to Puerto Rico Governor Ricardo Rossello.

Congress in October approved $4.9 billion in disaster relief loans to Puerto Rico and the U.S. Virgin Islands as part of a broader hurricane aid package, but Rossello is claiming the Treasury Department has not yet ponied up the money, and he’s asking lawmakers to intervene.

Assistance for the cash-strapped island, whose finances were in dire shape even before the deadly hurricanes last year, has been a topic in previous high-level spending negotiations. It may be on the table once again this month.