WASHINGTON, D.C. -- Americans' support for the United States' taking military action against the Syrian government for its suspected use of chemical weapons is on track to be among the lowest for any intervention Gallup has asked about in the last 20 years. Thirty-six percent of Americans favor the U.S. taking military action in order to reduce Syria's ability to use chemical weapons. The majority -- 51% -- oppose such action, while 13% are unsure.

Americans also opposed military intervention in Syria in a May Gallup survey. In that poll, by 68% to 24%, Americans opposed military action "to attempt to end the conflict" if "all economic and diplomatic efforts fail to end the civil war in Syria."

Support is now somewhat higher, perhaps because of new allegations, from the U.S. and other nations, that Syrian President Bashar al-Assad's government used chemical weapons against his own people, resulting in mass casualties. However, the current question specifies a reason for the action -- to reduce Syria's ability to use chemical weapons, a narrower goal than ending the civil war, which is how Gallup previously asked about intervention.

Among recent past conflicts on which Gallup gauged public opinion prior to U.S. action, support was highest for intervening in Afghanistan and lowest for the 1999 conflict in Kosovo. Americans were divided about U.S. participation in the NATO bombing in Serbia's Kosovo region about a month before the NATO campaign began. The similarity is noteworthy because some analysts are comparing a potential strike in Syria with that military episode, in terms of scope, duration, and purpose.

The other three military engagements Gallup asked Americans about before they began -- in Iraq in 2003, Afghanistan in 2001, and the Persian Gulf in 1991 -- were all on a larger scale than what President Barack Obama proposes to do in Syria, and involved sending U.S. troops into foreign countries. All of these proposed military operations received majority support before they began. Notably, all of these conflicts, in Iraq, Afghanistan, and the Persian Gulf, were authorized by Congress and/or the United Nations at the time of the polling. Congress is currently debating whether to authorize military force in Syria.

Though Low, Support Level Could Change if Action Is Taken

If history is any guide, Americans' support for intervening in Syria may increase if the U.S. uses military force, due to what is known as a "rally effect."

Over the past 20 years, Americans' support for U.S. military engagements at the beginning of conflicts has traditionally been quite high, with an average of 68% of approving of 10 previous newly commenced conflicts.

The 1999 Kosovo/Balkans and 2003 Iraq conflicts are the clearest examples of the rally effect. Americans' backing of the bombing campaign in the former Yugoslavia climbed to majority levels once the United States became militarily involved. The 2003 Iraq war is even more dramatic: 56% of Americans favored taking military action against Iraq in Feb. 3-6, 2003, polling, about a month before the conflict began. By March 17 of that year, when war with Iraq was imminent, American approval of the coming conflict had risen to 66%. A day after the war began, support climbed to 76%.

Public support for action in Syria may also be bolstered by congressional authorization. Two wars with high levels of initial approval, Afghanistan in 2001 and Iraq in 2003, were authorized by Congress via legislation. However, both conflicts took place in a national security climate still deeply influenced by the tragic Sept. 11, 2001, attacks. Importantly, despite robust initial support and congressional authorization, many Americans now see these two wars as mistakes, perhaps due to the protracted U.S. engagement in those countries.

Democrats Divided on Action; Republicans and Independents Opposed

Americans have seen more recent wars through partisan lenses. This is true again in Syria's case, with Democrats divided on whether to intervene and a strong majority of Republicans opposed.

Independents also swing strongly against taking action, with 53% opposed. That more Democrats than Republicans support action -- a sharp reversal from the Iraq war, which Republicans were more supportive of -- is likely because a Democratic president is proposing these war measures.

Surprisingly, liberals and conservatives both skew against military action, while moderates are more divided.

More Americans Now Following News of Syria

The 71% of Americans who say they are following news about the civil war in Syria very or somewhat closely is up from 48% in June -- and higher than Gallup's 60% average for attention paid to hundreds of past key news events.

Implications

As Congress debates granting the president of the United States the authorization to use military force that he deems necessary to stop the use of weapons of mass destruction in Syria, the American public is mostly against such action. Support has grown marginally since earlier this year, but a slight majority remains opposed.

Americans, at least initially, were much more supportive of previous military engagements. But after more than a decade of conflict in Afghanistan and Iraq, war fatigue may be lingering. This is evidenced not only by Americans' relatively low level of support for U.S. intervention in Syria, but also the less-than-majority post-intervention approval (47%) of the 2011 military action in Libya.

Historically, Americans often rally around military actions once engagement begins, and should Congress authorize U.S. action in Syria, this may also heighten support for it -- if it occurs. Currently, though, much of the nation would rather sit this one out.

Editor's Note: Data in graph 1 were modified to be consistent with data published in this report -- data from a March 14-15, 2003, poll rather than a Feb. 24-26, 2013, poll on question of military action in Iraq are now cited and data on military action in Iraq/Persian Gulf are now the data for a slightly different question wording.