On Thursday (November 14), students at a high school just north of Los Angeles, California, were on lockdown. At least two students were killed and several others were injured when an armed classmate attacked Saugus High School in Santa Clarita.

That same morning, Senators Chris Murphy and Richard Blumenthal of Connecticut were in Washington, D.C., attempting to pass a universal background check bill, H.R. 8. Murphy and Blumenthal have been attempting to pass gun reform bills with particular urgency since the Sandy Hook massacre in Newtown, Connecticut, in which a perpetrator killed 26 people, including 20 children between six and seven years old. The bill the senators had been advocating for last week focused primarily on not allowing anyone in the U.S. to buy a firearm if they cannot pass a background check; they had been trying to bring it to vote for months. The bill passed the House of Representatives with some bipartisan support in February, but, like other progressive bills, has been held up in the Senate, where Mitch McConnell (R-KY) serves as majority leader.

Murphy didn’t know about the shooting until after he attempted to pass the bill, but Blumenthal was speaking to the Senate about why they should pass the law when he was handed a note about Saugus High School, ABC News reported. “As I speak on the floor right now, there is a school shooting in Santa [Clarita], California,” Blumenthal said. “How can we turn the other way? How can we refuse to see that shooting in real time, demanding our attention, requiring our action? We are complicit if we fail to act. It is not just a political responsibility, it is a moral imperative.”

The bill was blocked by Senator Cindy Hyde-Smith, the Republican senator from Mississippi who objected to the bill, told BuzzFeed News that the legislation “should not be fast-tracked by the Senate.”

“Many questions about this legislation need to be answered before it’s forced upon law-abiding gun owners,” Hyde-Smith said. She did not elaborate on which questions need to be answered, nor did she immediately respond to a request for comment from MTV News.

As Murphy told MTV News, “Under our rules, all it takes is one senator to object. And a senator from Mississippi stood up and said that she objected to the background check bill being brought up for a vote."

“My Republican colleagues had made it pretty clear that they are not going to change their mind,” Murphy added. “I've gotten pretty used to the idea that these school shootings are not going to change the minds of my Republican friends. Ultimately, we're going to have to beat them. And ultimately, we have to get people elected to Congress who are moved to action by these school shootings because no matter whether the number is two or 10 or 20 or 50, none of it seems to change the mind of people who have been in Washington [D.C.] for decades.”

Some of the Republicans who oppose this specific bill, and stricter gun control legislation in general, say that background checks violate Second Amendment rights, even though the Founding Fathers ensured “the right of the people to keep and bear arms” decades before manufacturers invented the kinds of guns available today. Even former Supreme Court Justice Antonin Scalia has said that the Second Amendment “is not unlimited. [It is] not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose."

During a recent phone interview, MTV News talked to Senator Murphy about why he thinks this bill is so hard to push through the Senate, why it’s time for reform now, and where we go from here.

MTV News: You asked the Senate to pass the Universal Background Check Bill on Thursday (November 14), nine months after it was passed in the House. Why did you choose to introduce it now?

Sen. Murphy: We asked the Senate to pass the bill yesterday because we're sick and tired of waiting. There are mass murders every single day in this country. Some of them get lots of news attention when they happen in schools, but there are shootings where multiple people are being killed in cities throughout the country every single day. And we're sick and tired of Congress doing nothing about it. So we went to the floor of the Senate yesterday and asked our colleagues to pass a bill that would require every single gun purchase in this country to come with a criminal background check.

The reality is lots of guns that are sold in this country today don't have a background check ... We want every single gun purchase to go with a background check. And if we pass that law, studies show that we could reduce gun murders in parts of the country by 20 or 30 percent. That would save literally tens of thousands of lives.

MTV News: When you brought this up, a Republican senator objected to it. Did that surprise you?

Sen. Murphy: I wasn't surprised. I expected that a Republican [might] come down and object to my motion. Of course, I didn't know at the time that, as I was making a move to try to bring the background check bill up for a vote in the Senate, news was breaking of another school shooting in California. It turned out to be pretty devastating to see Republicans objecting to anti-gun violence legislation being brought before the Senate right at the moment that the country was learning of another mass shooting. But I've kind of gotten used to this.

What we need to do now is make sure that we have voters who are really tuned into this issue, who are going to vote out people who aren't supporting gun legislation because I'm not sure we're going to be able to convert them. I'm not sure we're going to be able to change their minds while they're still in the Congress.

MTV News: How did you hear what happened in California? Was it before or after Sen. Hyde-Smith objected to the bill?

Sen. Murphy: I gave my remarks on the Senate floor, I asked for permission to bring up the background check bill, and then after the objection was raised, I went back to my office. As soon as I walked into my office I was told that, while I had been on the floor, news broke of this shooting. I was meeting with a Sandy Hook family member who asked for a few minutes to compose himself because he was so distraught at another school shooting. It was a reminder to me that, whenever one of these school shootings happen, people who have been through them before — the parents who've lost kids at Sandy Hook, Parkland, and Virginia Tech — go through that trauma all over again.

MTV News: How would this bill and bills like it better protect students?

Sen. Murphy: There's no one piece of legislation that's going to stop all shootings, whether it be in schools or in neighborhoods. ... We do know that if we pass a universal background check bill, we are going to save lives. Less dangerous people will get guns and there'll be less shootings.

There are some mass shootings where the individual got the gun without a background check. This summer there was a mass shooting in Odessa, Texas where seven people were killed, 20 were injured, and the shooter in that state was denied a gun at a gun store. But then he just found a place in Texas that didn't require a background check — an internet sale — and he was able to get the gun that killed seven people. So that's why we need to close these loopholes because the everyday gun crimes that happen in our city neighborhoods can be reduced by getting more illegal guns off the streets. And some of these mass shootings are, in fact, carried out by guns that were purchased through these loopholes.

MTV News: If there isn’t one piece of legislation that's going to end gun violence in the U.S., what are some other ways that you can achieve this and better protect students and everyone traumatized by gun violence?

Sen. Murphy: While the [perpetrator] in Santa Clarita had a pistol, the weapon of choice for most of these mass school shooters is the AR-15. This is a weapon that is designed to kill as many people as quickly as possible. In less than five minutes of shooting an AR-15-style weapon killed 20 kids [at Sandy Hook].

If we ban these assault weapons and if we ban these high-capacity magazines that hold 30 or a hundred bullets, [I believe] we'll cut down on the number of people who are killed in these mass shootings but will also probably cause some of these mass shooters to not actually do it in the first place.

This interview has been edited for clarity and length.