Where does US gun control go from here?

Every recent mass shooting in America has been followed by an increasingly familiar political drama: Democrats call for new gun-control measures, such as a ban on assault-style weapons, and point out how the US is alone among industrialised nations in its high levels of gun violence.

Republicans counter that the right to possess firearms is enshrined in the US Constitution and that new gun-control legislation would be counterproductive.

Then, because of the nature of US government, little changes on a national level.

"We have to do more to stop gun violence," US President Joe Biden said after the April mass shooting that killed six at a school in Nashville, Tennessee. "It's ripping our communities apart."

But doing more, at least on the national level, faces a number of serious obstacles.

Here's a look at some of those challenges.

In the weeks after 20 children and six adults were killed at Sandy Hook elementary school in Connecticut in 2012, a majority of US senators supported passing legislation requiring expanded background checks for gun purchases.

But because of the filibuster - a parliamentary procedure that requires at least 60 votes in the 100-seat Senate to pass most legislation - a simple majority was not enough.

After another school tragedy in Uvalde, Texas, in 2022, the House of Representatives, then controlled by the Democrats, approved an assault-weapons ban but the measure stalled in the Senate.

Although polls indicate majorities of Americans support such an effort, many Republican senators represent states with large pro-gun communities.

And the Republican voters whose support lawmakers need to win primary elections (the selection process within each party) are even more opposed to reform. So unless sentiment shifts among that constituency, the Republicans are unlikely to change course.

With the House of Representatives back in Republican hands, it is more probable that the chamber will try to expand gun rights, not limit them.

Although congressional efforts at sweeping gun control were stymied in 2015, gun-control activists made substantive progress in passing new laws at the state level.

In Connecticut, for instance, there was overwhelming support for reform from the communities still reeling from the brutality of the Sandy Hook attack. Other Democratic-controlled states - like New York, Maryland and California - passed their own legislation, closing gun-show loopholes, limiting magazine sizes and prohibiting the sale of certain types of firearms.

But the states that have the political majorities to pass gun-control regulations have already done so. And in many Republican controlled states, the momentum on the gun issue is towards less regulation, not more. In April, Florida became the 26th state - all Republican - to allow its residents to carry a concealed handgun without a government licence.

Democratic politicians in those states, frustrated by the lack of progress, have cited recent school shootings as reason to act. Nashville Mayor John Cooper denounced what he called the "cult of the gun" in comments made shortly after his city's violence.

"The country needs to pick itself up and say no to an assault weapons lobby that again is making it too available and too convenient and too first-of-mind for people to go out and commit terrible acts," he said.

Tennessee is one of the states with broad protections for permitless gun ownership - a fact that the state's national politicians have celebrated. In 2021, Nashville's congressional representative Andy Ogles sent a Christmas photo of his family in which all but the youngest child was carrying some type of firearm.

"The very atmosphere of firearms anywhere and everywhere restrains evil interference - they deserve a place of honour with all that's good," the congressman said in a holiday message accompanying the photo online.

Even if the political calculus changes in Congress or among states hostile to enacting gun-control legislation, there is a significant and growing obstacle to any attempts at reform - the courts.

In 2008, a narrow 5-to-4 majority in the US Supreme Court ruled that the Second Amendment to the US Constitution, which says "the right of the people to keep and bear arms shall not be infringed", guarantees a personal right to possess a handgun.

That interpretation, although subject to furious debate, has embedded gun ownership rights in the text of the Constitution itself. And since that decision, the courts have only become more supportive.

One of President Donald Trump's lasting legacies was to appoint hundreds of conservative judges to the federal courts, including naming three new Supreme Court justices.

Last year, two Trump-appointed appellate court judges in California struck down a state law prohibiting the sale of assault rifles to those under the age of 21.

That opinion, if upheld by the Supreme Court, could be of particular relevance given that the perpetrators in Uvalde and Sandy Hook fall into that category.

"America would not exist without the heroism of the young adults who fought and died in our revolutionary army," one of the judges wrote. "Today we reaffirm that our constitution still protects the right that enabled their sacrifice - the right of young adults to keep and bear arms."

Last year, the Supreme Court struck down a New York law that restricts who may obtain concealed handgun licences in the next month, with Justice Clarence Thomas firmly grounding a broad right to own and carry firearms in the Second Amendment to the US Constitution.

"The Second Amendment guaranteed to all Americans the right to bear commonly used arms in public subject to certain reasonable, well-defined restrictions," he wrote in a 6-to-3 opinion that was joined by the five other conservative justices on the court.

With gun laws already on the books being ruled unconstitutional, it appears likely that any new laws will face legal challenges as well - and may not survive long.