Almost immediately after a gunman in Las Vegas mowed down dozens of people and injured hundreds of concert-goers last fall, there was unprecedented openness among many Republicans in Congress for some kind of gun control legislation.
Yet more than four months after the deadliest shooting in modern US history, Congress has yet to send any firearm-related bill aimed to curb gun violence to the President's desk.
On Wednesday, 17 students were killed at a Florida high school, invoking the same sense of fury and outrage seen time and time again, as Washington once more became the epicenter for the emotional debate over how to break a continuous loop of massacres.
Within hours of the Florida shooting Wednesday, Democratic Sen. Chris Murphy of Connecticut, who came into the Senate just weeks after the Sandy Hook Elementary school massacre in 2012, took to the Senate floor and blamed Congress "for a level of mass atrocity that happens in this country with zero parallel anywhere else."
Democratic Rep. Jim Himes, another lawmaker from Connecticut, said the next few days in Congress will be all too familiar.
"There's sort of just a sense of resignation here right now," Himes said on CNN's "The Situation Room." "The pattern will be perfectly predictable. There will be a moment of silence. People will wish everybody thoughts and prayers and sympathy for the victims, and then the Congress of the United States will do absolutely nothing."
Senate leaders took a moment of silence for the victims in Florida, but there was no plan as of Thursday morning by Republicans who control Congress to take any legislative action.
The standstill reflects a fundamental difference between most Democrats and most Republicans on the question of gun control. Republicans -- for both political realities and their core beliefs -- don't see restrictions on guns as the answer to gun violence.
"I want to begin this morning by sharing the shock and sorrow that all of us in this body felt as we learned of yesterday's shooting," Senate Majority Leader Mitch McConnell said on the Senate floor. "To say that such brutal, pointless violence is unconscionable is an understatement. Schools should be places where children can learn, and faculty and staff can work, without fear of violence."
After Las Vegas
There was some action related to gun violence in Congress last fall, but nothing has been passed into law. While there's no evidence that these efforts would have prevented the Florida shooting, pro-gun control activists and many Democrats are desperately pleading for Congress to take any kind of action related to gun violence.
Just days after the Las Vegas shooting in October, a bipartisan group of lawmakers introduced legislation to ban the sale of bump fire stocks, a type of a device that enables semi-automatic rifles to fire more rapidly, similar to automatic weapons. Twelve of them were found on firearms recovered from the gunman's hotel room.
The bill has gone nowhere, as Republicans instead have largely decided to defer to the Bureau of Alcohol, Tobacco, Firearms and Explosive to make a regulatory change rather than pursue a legislative one in Congress. That removes the issue from a politically toxic environment in Congress, where a legislative fix would be uncertain.
The rulemaking process kicked off in December. The estimated timeline for a ruling, congressional sources told CNN, is eight to 12 months.
Also, the House passed legislation in December that would direct the Bureau of Justice Statistics to study all crimes involving firearms and report back to Congress in six months about how many involved weapons with bump stocks.
A little more than a month after Las Vegas, a gunman killed 26 people at a church in Texas. The shooter had previously been imprisoned for domestic abuse, but the Air Force didn't convey that information to the National Instant Criminal Background Check System , which should have prevented him from buying the guns used in the mass shooting.
That provoked bipartisan support for legislation that would improve the background check system to ensure that states and the federal government upload required background check information into the system.
While the House passed a bill that included this provision in December, a Senate bill with the same proposals -- sponsored by Murphy and Sen. John Cornyn, the No. 2 Republican in the Senate -- has stalled. It's been referred to the Judiciary Committee, but it has not been taken up for a vote.
Republican Sen. Chuck Grassley, who chairs the Judiciary Committee, weighed in on the Florida shooting Thursday, though he did not speak specifically about the background check related bill.
"It seems to be common for a lot of these shootings, in fact almost all of the shootings, is the mental state of the people," Grassley said. "And we have not done a very good job of making sure that people that have mental reasons for not being able to handle a gun getting their name into the FBI files, and we need to concentrate on that."
Pro-gun control activists and many Democrats in Congress were furious in December when the House approved legislation that would loosen gun regulations and allow those with permits to carry concealed weapons to legally travel with those firearms to other states, a top priority of the National Rifle Association.