Barack Obama vowed not to take America into another war unless it was “absolutely necessary” after noting in Memorial Day remarks that for the first time in nine years soldiers were no longer dying in Iraq.

At a service to remember the country’s fallen at Arlington National Cemetery in Virginia, the president also said that US forces are withdrawing from Afghanistan.

“After a decade under the dark cloud of war we can see the light of a new day on the horizon,” the president said to applause from an audience that included the relatives of many of those who have died in recent conflicts.

Obama later attended an event to commemorate the 50th anniversary of the escalation of US involvement in Vietnam, at which he described the treatment of veterans who served in the south-east Asian conflict as a “national disgrace”.

“You were often blamed for a war you didn’t start when you should have been commended for serving your country with valour,” the president told those gathered at the Vietnam Veterans Memorial in Washington.

“It was a disgrace that should have never happened,” he added.

Earlier, having reflected on the scaling down of conflict in Iraq and Afghanistan under his watch, the president vowed he would not take the US into another war if he can possibly avoid it.

The comments appeared in part to be a swipe not only at his predecessor over the discredited justifications for the rush to invade Iraq but a response to increasingly belligerent Republican opponents pressing for a more strident attitude toward Iran and Syria.

“As commander-in-chief I can tell you that sending troops into harm’s way is the most wrenching decision that I have to make. I can promise that I will never do so unless it’s absolutely necessary. And that when we do, we must give our troops a clear mission and the full support of a grateful nation,” he said.

Obama lays a wreath at the Tomb of the Unknowns. Photograph: Kristoffer Tripplaar/EPA

Obama said that with the war in Iraq finally over, it was fitting to pay tribute to the sacrifices made in that conflict.

“Especially for those who have lost a loved one, this chapter will remain open long after the guns have fallen silent,” he said.

The president recalled that the first US military casualties of the Iraq war came on the first day of the invasion when four Marines died in a helicopter crash on the border. He said that eight years, seven months and 25 days later, David Hickman became the last American casualty when his vehicle struck a roadside bomb in Baghdad.

“To the families here today, I repeat what I said to the Hickmans: I cannot begin to fully understand your loss. As a father, I cannot begin to imagine what it’s like to hear that knock on the door and learn that your worse fears have come true,” he said.

Nearly 4,500 US soldiers died in Iraq. The Vietnam Veterans Memorial carries the names of 58,282 US soldiers killed in the conflict.

South African president Jacob Zuma is taking an artist and a gallery to court to have a painting depicting him as a Lenin figure with his genitals exposed taken down. His spokesman says the painting “undermines the esteem of the highest office in the land and impugns the president’s constitutional right to dignity”. His court papers further say his reputation has been tarnished. His children issued a press release and joined him in court, saying the artist has no respect for their father.

Here in South Africa we have been talking about President Zuma’s sexual peccadilloes for a long time. Zuma, who was accused of rape in 2006(and later cleared), has 21 known children. When he married his latest wife – his fourth current wife and his sixth in total – Zuma told her: “Those who came before you didn’t close the door on you and no one closed the door on them. So I expect you to do the same.”

Analysis of his presidency never concludes with policy discussion – on which Zuma has proven weak – but with his sexual lifestyle. Columnist Mondli Makhanya wrote this week:

“In every other conversation, the debate about the president is not about his political, economic and societal vision, but about which bodily form he is gazing at … the president can spend one whole weekend celebrating his wife’s 40th birthday, spend the following weekend celebrating his own 70th birthday with his three wives and his fiancee, and then spend the entire following weekend turning the fiancee into a full wife. Three weekends of fantastic fun. This is a wonderful country. Truly wonderful.”

Makhanya had his tongue firmly in cheek, of course. In truth, the damage Zuma has done to the image of the black man everywhere is untold. If the image of his two predecessors, Nelson Mandela and Thabo Mbeki, was of nation-builders and cool intellects, Zuma’s is of a man whose concentration is on sex and political self-preservation. He has done more to provide fodder for racist stereotypes than any black South African has done.

Thankfully, enough of us know that the stereotype is false. So what is Zuma’s argument? There is nothing in our constitution that enjoins us to respect the head of state, or to genuflect before him. This is a constitutional democracy, not a monarchy. Respect is earned, and very few would say that the president has earned our respect given his lifestyle. Meanwhile, last week schoolchildren had to go to court to force him to provide books still outstanding six months into the school year. His reputation on this score is in tatters.

All this, however, is irrelevant when one considers South Africa’s constitution – hailed by many as among the most progressive in the world – and its bill of rights. The right to free expression is entrenched. This includes the artist Brett Murray’s right to artistic creativity. In turn, the constitution protects Zuma’s right to privacy and dignity.

As a public figure, however, Zuma’s rights in this regard are limited. Further, his flaunting of his sexuality – he arrives at government functions with all his wives in tow and enjoys suggestively belting out his signature song “Pass Me My Machine Gun” – makes him fair game for cartoonists, artists, satirists and newspaper columnists.

But this is not to say that South Africans are united on this issue. My friend of 25 years was among those who turned up at court in Johannesburg yesterday to have the painting pulled down. He was not there, he told me, to support Zuma. He was there because “in African culture” such depictions are disrespectful.

The culture argument is a nonsense. Just last week an ANC MP said gay people can be cured by a traditional healer because homosexuality was not part of “African culture”. Further, African culture is not homogeneous. And our constitution does not provide for it in any case.

The painting was defaced yesterday. Yet the debate – which has now included death threats against the artist – must go on. If Zuma wins the right to have the painting banned then we must expect to see a country that bends to populism and patriarchal conservatism and not the progressive South Africa which boasts a constitution adopted in Mandela’s day. Today it is an artist. Tomorrow it could be abortion, and gay people, and cartoonists, and books.