After the deadliest mass shooting in U.S. history in Las Vegas last year, lawmakers discussed imposing restrictions on "bump stocks." The Las Vegas shooter used that type of gun modification, which makes a semi-automatic weapon fire like an automatic weapon, and killed 58 people.
After a gunman killed 26 people at a church in Sutherland Springs, Texas, last November, lawmakers discussed how they could improve the background check system.
No new laws came of those discussions.
Now, after a gunman killed 17 people at a Florida high school, President Trump has given some indication of what he thinks could stop further shootings.
"We are committed to working with state and local leaders to help secure our schools and tackle the difficult issue of mental health," he said in a statement.
Whether that will inspire legislation remains to be seen. Mass shootings often inspire gun-control legislation — legislation that, in recent years, more often than not has languished.
While the president and members of Congress consider how to respond to the Florida shooting, the tool below allows you to see how your state's representatives and senators have voted on major gun legislation over the last two and a half decades.
Because some bills aim to loosen gun restrictions (such as the February 2017 bill to ease restrictions on mentally ill people's ability to get firearms) and some bills aim to tighten them (Dianne Feinstein's 2016 amendment to stop people on the terrorist watch list from getting guns), we have color coded people's votes in terms of whether they — broadly speaking — voted to increase or decrease gun restrictions.
Votes below include senators' votes from when they were in the House, if they ever served there.
Note: Alabama Republican Sen. Richard Shelby was a Democrat until 1994, when he changed parties.
And here's a brief description of each bill represented above:
Brady Bill (1993, House and Senate): Enacted into law. Refers to the Brady Handgun Violence Prevention Act. Passed in 1993, the Brady bill established five-day waiting periods and required background checks for gun purchases.
Assault Weapons Ban (1994, House and Senate): Enacted into law, expired in 2004. This law banned people from making, selling, or owning certain types of semiautomatic weapons.
Closing Gun Show Loophole (1999, House and Senate): Did not become law. This refers to separate measures in each chamber that would have (broadly speaking) required people purchasing guns at gun shows to undergo a background check and a three-day waiting period.
Protection of Lawful Commerce in Arms Act (2005, House and Senate): Enacted into law.This measure protects firearm manufacturers from being sued for crimes committed with the firearms they manufactured.
Concealed Carry Reciprocity (2011 and 2017, House; 2013, Senate): Did not become law.These bills would have allowed a person with a concealed-carry permit in one state to legally carry a concealed firearm in other states.
Manchin-Toomey Bill (2015, Senate): Did not become law. This bill would have required background checks for the purchase of guns at gun shows and online.
Murphy Amendment (2016, Senate): Did not become law.This measure would have expanded background checks to cover guns sold online and at gun shows.
Feinstein Amendment (2016, Senate): Did not become law. measure would have barred people on terrorist watch lists from buying firearms.
Mental Health (2017, House and Senate): Enacted into law. This bill undid an Obama-era regulation that added some people with mental illnesses to the FBI's background check database.
Part of the reason some gun laws fail, as stated before, is that gun control votes tend to fall so sharply along party lines. But the data show that Democrats, who favor gun control more than Republicans, tend to be more likely than Republicans to break ranks.
Of the bills we analyzed, here is how House votes broke down within the two parties
On the Senate side, the split is more straight along party lines, but there are a few exceptions, for example, with the 2005 Protection of Lawful Commerce in Arms Act.
We broke out the people who broke with their party most often on the bills we studied here. On the Senate side, North Dakota Sen. Heidi Heitkamp has voted against stricter gun control (or for looser gun control) on every major gun control bill we studied since she took office in 2013. In the chart below, a white X denote votes where a member of Congress voted differently from most of their fellow party members.
And on the House side, Georgia Democratic Rep. Sanford Bishop has voted against his party on five gun control bills.
Again, though, there are more gun control bills than represented here. The point isn't to capture every gun bill vote ever, but to allow people to see how the people who represent them have voted on some key pieces of legislation.
Data collected by Abigail Censky, Madeline Garcia, Danielle Kurtzleben and Lexie Schapitl/NPR. Design and development by Alyson Hurt and Danielle Kurtzleben/NPR.