Americans support President Barack Obama's campaign of air strikes against Islamic State militants but have a low appetite for a long campaign against the group, a Reuters/Ipsos poll showed on Friday.
Sixty-four per cent of people in the online survey said they backed the campaign, which Obama said in a televised address this week is being escalated and spread beyond Iraq to Syria. Twenty-one per cent were opposed and 16 per cent said they did not know.
The poll result is good news for Obama as he tries to build support at home for attacking IS, as well as putting together a coalition of allies against the militant group which has taken a swath of territory in Iraq and Syria.
Weary after years of ground war in Iraq and Afghanistan, Americans look favourably on air strikes because they are less risky, said Ipsos pollster Julia Clark.
"People see air strikes as surgical. They think we are able to go in and do something that affects in a negative way this horrible group of people and we are able to extract ourselves with only a very low risk to American lives," she said.
But when asked if they supported the air campaign even if it lasts two or three years, the proportion of those in favour dropped to 53 per cent. Twenty-eight per cent were against a long air campaign and 19 per cent said they did not know.
"There's absolutely no appetite for re-engagement in that region in any prolonged way so we see that support drop off," Clark said.
The poll was conducted almost entirely after Obama's speech about Islamic State on Wednesday night.
Obama's plan to fight Islamic State simultaneously in Iraq and Syria thrusts the United States directly into the midst of two different wars, in which nearly every country in the region has a stake, alliances have shifted and strategy is entangled with Islam's 1,300-year-old rift between Sunnis and Shi'ites.
Islamic State is made up of Sunni militants, who are fighting against a Shi'ite-led government in Iraq and a government in Syria led by members of a Shi'ite offshoot sect.
It also battles against rival Sunni Islamists and more moderate Sunni groups in Syria, and Kurds on both sides of the border.
In the last month, Islamic State outraged many Americans by beheading two US journalists whom it had held captive.
When asked what is the best response to the threat posed by the Islamic State, 44 per cent of people in the Reuters/Ipsos poll said air strikes while only 9 per cent favoured sending American troops to fight the militants.
Poll respondent Aggie Kuhn, a retired nurse from Ellis in western Kansas, said she strongly favoured strikes in part because the United States was partially responsible for Iraq after invading the country in 2003.
"I think we do have a responsibility," she said. "We started things over there."
But she was more lukewarm to the idea of a drawn-out air campaign, especially if countries neighbouring Iraq and Syria are not supportive of US military action.
"We have to re-evaluate our position and re-evaluate where the people nearby are. Are we getting support from them? Where is the rest of the international community? It's not one of these things where you want to get into it for 10 years," Kuhn said.
A quarter of respondents said the United States should fund and support a multinational intervention against the group.
A total of 988 people answered the questions about whether Americans support or oppose air strikes from Sept. 10 to 12.
For the question on the best response to Islamic State, 522 people responded on Sept. 11 and 12.
The precision of the Reuters/Ipsos online polls is measured using a credibility interval. In the questions about support from air strikes the credibility interval was 3.6 percentage points. It was 4.9 percentage points for the question about the best response.