AS hecklers tend to be, the person who interrupted President Obama's speech was loud but unintelligible.

Yet the president, hosting a reception for LGBT Americans in the White House, could not have been clearer in his response. "You are in my house," he said to cheers, "it's not respectful."

Earlier in the week, Mr Obama had dropped the N-bomb during an interview on racism in America. It had been just days since the murder of nine black Americans at the Emanuel Methodist Church in Charleston, South Carolina, and the president was in no mood to tiptoe around. America is not cured of racism, he said. "It is not just a matter of it not being polite to say n***** in public. That's not the measure of whether racism still exists."

With a year to go in his presidency, it appears that the country's first black president is ready as never before to declare "my house, my rules" when it comes to racism in America. Little wonder. The murders of churchgoers in Charleston shocked the US and the world, but one has to wonder whether even this outrage can bring about the seismic change needed. The Charleston killings happened in 2015 America. The accused gunman, Dylann Roof, is just 21 years old. Born in 1994, 30 years after the Civil Rights Act, Roof should have been part of a generation that learned about America's struggle against racism in history class, not someone who had the poison pumping through his veins. How has America travelled so far on race, to the extent of electing a black president, yet made so little fundamental progress?

It is a question as complex as it is pressing. Just as hecklers are wont to be loud but unintelligible, so humans facing a persistent, seemingly intractable problem tend to focus on what they can change in the short term. So it is that America has this week gathered around the Confederate flag, as brandished by the Southern, slavery supporting states during the American Civil War, and asked why on earth it is still being flown in parts of the country.

It is not such a leap to go from the events in Charleston to the debate now taking place over that flag, whether it appears on car licence plates or flying over the State House in Columbia, South Carolina. In a piece published yesterday on The Conversation website, John Brewer, Professor of Post Conflict Studies at Queen's University Belfast, writes: "It may seem strange to some that in a country wracked by gun violence, race inequalities and hate crime, the discussion has become one about symbolism. But symbols matter. Flags, emblems, lapel badges, car stickers and the like are all ways of expressing belonging, of conveying what is important to us and the groups with which we identify. They can be used to both communicate and construct identity."

Dylann Roof photographed himself with the Confederate flag as a way of showing who he was and what he stood for. Another photograph shows him burning the Stars and Stripes. No attachment to Old Glory was aflame in this young man's breast. It is hardly the first time the Confederate flag has been draped in shame, but a week on from Charleston this relic of the past is casting a shadow across American politics, to the extent it is dominating the 2016 race for the White House, and the Republican contest in particular.

Mitt Romney, who unsuccessfully challenged Mr Obama in 2012 and will have some influence in who the Republican candidate turns out to be next time, was certain where he stood. Get the flag over the State House down, he said, because for many it is a symbol of racial hatred. Jeb Bush has been through the Confederate flag argument before. As governor of Florida he took the flag down and put it in a museum "where it belonged". Now the Republican South Carolina governor, Nikki Haley, has joined the haul-it-down movement, calling the flag a "deeply offensive symbol of a brutally offensive past".

Given the lead taken by prominent Republicans, one would assume presidential hopefuls would be tripping over each other to back the calls. But not so. Some, such as Marco Rubio, argue that states, in this case South Carolina, should be left to make up their own minds. Demonstrators against the flag are having none of it, their placards proclaiming that what the Confederate flag represents is hate, not heritage, and it should go.

So America returns to the age-old quandary: how to balance rights and freedoms in a country that is home to some 320 million people. There is another statistic here which is pertinent - the number of guns in America. Though estimates vary, the tally has been put at between 270 million to 310 million. This is a nation, in other words, with almost as many privately owned guns as there are people. Can a president begin to tackle racism in America without tackling gun control at the same time? A hateful opinion on its own does not kill. But a hateful mindset, allied to the freedom to buy guns, has too often resulted in appalling bloodshed.

Even the most optimistic supporter of the President has little hope, however, that he can achieve anything on gun control in what is left of his second term. He has said as much himself, stating that the "grip" of the National Rifle Association on Congress is extremely strong. Change won't happen, he argued, "until the American public feels a sufficient sense of urgency and they say to themselves, 'This is not normal. This is something that we can change and we're going to change it'." After every atrocity there is certainly a sense of urgency, a feeling of something has to be done, but that something has not translated into gun control. As long as America continues to feel pride in preserving the freedom to bear arms, the shame of mass shootings will have no effect on gun policy.

If the president is heading nowhere fast on gun control there is at least some hope that he is taking the initiative on race. President Obama has been a lifelong campaigner on civil rights, his commitment never in doubt. But he has seemed unwilling to let the matter of race dominate his presidency, and up till now that has been the right course. Yet something has changed, has put fire in his belly, and it could be argued that it happened several years ago, before Charleston horrified the nation. Commenting on the 2012 fatal shooting of Trayvon Martin, an unarmed 17-year-old, the president said "this could have been my son". At once, an issue that had always been personal for the president had become very public and intensely political.

Which is not to say significant progress will happen any time soon. On that front, the times continue to change at a painfully slow pace, but they are changing. And they will do so even further and faster as America's shifting demographics have more of an impact at the ballot box. For now, change must come where it can, starting with taking down that grisly flag.