Once again, the Senate will vote on gun control in the aftermath of a mass shooting — this time the nation’s worst in modern history. A man who pledged allegiance to the Islamic State strafed a gay nightclub in Orlando on June 12, killing 49 people.  

Monday’s votes on four gun-related amendments will come amid debate on a multi-agency spending bill that includes funding for the Justice Department.  

The measures — aimed at preventing suspected terrorists from buying guns and expanding background checks for firearms purchases in certain circumstances — will require 60 votes to pass.  

But approval appears unlikely in a chamber that failed to tighten gun laws following the 2012 massacre of 26 people — most of them kids — at Sandy Hook Elementary School in Newtown, Connecticut, or the shooting of more than a dozen others in San Bernardino, California, last year.
Democratic Sen. Christopher S. Murphy invoked the Sandy Hook shooting in his home state during a 15-hour filibuster last week that prompted an agreement by Senate leaders to consider the new gun proposals on Monday.  

Here are five things to watch:

It’s ‘Groundhog Day’

The Senate last voted on gun amendments in December after the San Bernardino shooting. Each side took a different approach to stop gun sales to suspected terrorists and both fell short of the 60-vote threshold.  

One amendment from Democratic Sen. Dianne Feinstein of California was rejected, 45-54, on a procedural vote. Another from Majority Whip John Cornyn, R-Texas, was rejected 55-44, failing to get the 60 votes needed to pass.   

This time, the anti-terror votes will again be on separate amendments from Feinstein and Cornyn.  

There’s little to suggest the outcome, however, will be any different this time.  

Maine GOP Sen. Susan Collins referred to the situation as “Groundhog Day” — a reference to the movie where the main character lives the same day repeatedly.  

And Murphy has his doubts that common ground can be reached on both counts. He told reporters Friday that while he’s “optimistic” the Senate might adopt a measure to prevent suspected terrorists from buying guns, he’s not sure there will be enough votes to expand background checks. He emphasized that talks were ongoing.

Keeping guns from terrorists

Feinstein has an amendment, which won over the FBI and the White House, aimed at stopping suspected terrorists from purchasing guns without blowing any investigations. The measure would allow the attorney general to stop gun purchases by those on terrorist watch lists.  

Republicans oppose it because they say it treads on Second Amendment rights and doesn’t give those denied a gun purchase an adequate way to appeal that decision.  

Cornyn is offering the Republican’s counter amendment that would allow a U.S. attorney to block the sale of a gun if he or she can show probable cause that the buyer is engaged in terrorism.  

Democrats have said the language would be unenforceable and wouldn’t stop potentially dangerous people from buying guns.  

Sen. Mark S. Kirk of Illinois, the most vulnerable Republican up for re-election in November, said Friday he will support the Feinstein amendment. When a similar proposal from the California senator came up in December, he was the only Republican to back it.  

Background checks

The other battle set up for Monday will include an amendment from Murphy that aims to expand the National Instant Criminal Background Check System by requiring a boost in how records are shared for identifying anyone who should be banned from purchasing guns. It would also require a background check for every gun sale, including those on the internet and at gun shows.  

Iowa GOP Sen. Charles E. Grassley is countering that with an amendment that would notify law enforcement if someone investigated for terrorism in the past five years tries to purchase a gun. Connecticut Democrat Richard Blumenthal said on a conference call Friday that Grassley’s measure doesn’t go far enough.

More gun amendments

There are a few Republicans floating their own measures on restricting access to guns, but it’s unclear which ones might gain traction and garner some kind of vote. These measures could be tried if the four votes already set up for Monday fail.  

Republican Patrick J. Toomey of Pennsylvania filed an amendment that aims to strike a middle ground between the Feinstein and Cornyn proposals.  

Collins has said she’s also working on an alternative gun measure that she hopes could gather bipartisan support. It would be limited to barring gun purchases for people on the no-fly list and a selectee list, not the broader terrorism watch list. People would be able to appeal in court.  

Republican Rep. John Boozman of Arkansas filed an amendment to require the FBI to process appeals on denials of gun purchases within 90 days without adding any money to the agency’s budget. Boozman filed another amendment to prevent the Justice Department from mandating that law enforcement use “smart gun” technology, a safety feature that only allows an authorized user to fire a gun.  

Democrat Kirsten Gillibrand of New York filed an amendment that would make it a crime of gun trafficking to sell more than one gun at a time under certain conditions.

Potential stumbling blocks

It’s not clear at this point whether other amendments to the spending bill might be debated on the Senate floor, much less receive any kind of vote. But they could light more political fireworks under a bill that already has generated the ninth-longest filibuster in the Senate since 1900.  

Barbara A. Mikulski of Maryland, the top Democrat on both the Senate Appropriations Committee and the subcommittee that crafted this bill, has an amendment that would provide $175 million in emergency funding to the FBI to help prevent terrorism and $15 million to the Justice Department for law enforcement training on active shooter situations. Mikulski designated the requests as emergency funding so she would not have to offset the cuts elsewhere.  

Speaking of emergency funding, South Carolina GOP Sen. Lindsey Graham says why not? He filed an amendment that would increase FBI funding by about $2.8 billion as emergency spending to fight domestic and international terrorism.  

The parties also have competing amendments on immigration, none of which is guaranteed a vote.  

Texas Republican Ted Cruz filed an amendment that would stop people from coming to the United States from any country with terrorist-controlled territory — specifically Iraq, Libya, Somalia, Syria and Yemen — with certain exceptions. Arizona GOP Sen. John McCain is proposing to increase by $850 million a grant program for local police to detain undocumented immigrants — and to cut a section of the 2010 health care law by the same amount.  

On the other side, Democratic leader Harry Reid of Nevada filed an amendment to stop immigration hearings for vulnerable children seeking asylum in the United States unless they are represented by a lawyer.  

And Oregon Democrat Ron Wyden filed an amendment that would prohibit discrimination based on “sexual orientation or gender identity,” an issue that has tripped up the House as it considers appropriations bills.  

It’s unclear if the House will take up any gun-control proposals.  

David Lerman contributed to this report.