President Trump's decision to launch missile strikes at a Syrian airfield in retaliation for a chemical weapons attack on civilians marks a major escalation in U.S. involvement in the country's civil war — and is an action that Americans overwhelmingly opposed four years ago.

But while it will take days to gauge Americans' reactions to Friday's strikes, history shows public support for military action can shift dramatically in the wake of it actually happening. And the somewhat tepid bipartisan congressional support we're seeing for Trump's move could provide a significant boost.

Surveys have found Americans generally support military action to stop genocide, but the 2013 debate laid bare the public's hesitation about forcefully punishing Syria for using chemical weapons.

In the month after the United States concluded that Syria had used chemical weapons in August 2013, three separate Washington Post-ABC News polls found clear majorities of the public opposed launching missile strikes in Syria. In the last of those surveys, 61 percent opposed strikes in response to Syria's use of chemical weapons, with opposition outpacing support by about a 2-to-1 margin. The margin of intense opinion was even starker: 45 percent said they “strongly opposed” military strikes that then-President Barack Obama advocated — nearly three times as many as the 17 percent who “strongly supported” the action.

And despite Obama's public endorsement of using military action, the opposition crossed party lines. Democrats opposed strikes by a 50-to-38 margin, with opposition ballooning to 64 percent among independents and 67 percent of Republicans.


The public's reasons for hesitation were clear in the survey and others, with fewer than half (45 percent) saying America's vital interests were at stake in Syria. A separate CNN-ORC poll found 58 percent of those who watched Obama's speech arguing for action said airstrikes “would not achieve significant goals for the United States.”

The Post-ABC poll also found overwhelming support for a diplomatic solution, with nearly 8 in 10 supporting a Russia-proposed plan to have Syria place its chemical weapons under control of the United Nations for eventual destruction. But Americans also expressed skepticism that this plan would be foolproof, with a clear majority saying they were “not too” or “not at all” confident that Syria would give up all its chemical weapons. (This turned out to be prescient; Syria ultimately agreed to turn its chemical weapons over but apparently did not completely do so.)

So why might support be higher this time around?

Trump's roughly 40 percent job approval rating represents a key barrier to support for his Syria actions, as long-running perceptions of him will undoubtedly color people's reaction. Obama's approval was at a higher 47 percent in Post-ABC polling after he unsuccessfully argued in favor of military strikes.

But if there's one lesson from the 2013 debates over action in Syria, it's that public support can change sharply in reaction to events. Months before the United States declared that Syria had used chemical weapons during its civil war, more than 6 in 10 Americans in a Post-ABC poll said they would support military involvement if the country's government used such weapons against its own people.

Although news of confirmed chemical weapons usage in 2013 appeared to dampen support for action, Trump's decision to take action — along with fairly positive reactions from Congress — could also boost support. The 1999 U.S. intervention in Serbia offers an example of this dynamic.

Just before President Bill Clinton announced the beginning of the air war March 24 of that year, a Post-ABC poll found Americans split down the middle — 47 percent in support and 47 percent opposed — on whether the United States should bomb Serbian targets if it did not agree to a peace plan. But in the days afterward, a Post-ABC poll found 60 percent supporting U.S. and European allies conducting airstrikes in Serbia, with majority support persisting for an additional seven polls over the following two months.

So far, Republicans leaders have expressed support for Trump's actions, with House Speaker Paul D. Ryan (Wis.) calling the strikes “appropriate and just.”

And with a few glaring exceptions, Democrats in Congress weren't immediately critical of the strikes themselves. Here's Rep. Adam B. Schiff (D-Calif.), the top Democrat on the House Intelligence Committee: “This strike will not hasten an end to the Assad regime, but it may deter its further use of chemical weapons.” Senate Minority Leader Charles E. Schumer (D-N.Y.) offered a more positive, if hedged, endorsement: “Making sure that Assad knows that when he commits such despicable atrocities he will pay a price is the right thing to do. It is now incumbent on the Trump administration to come up with a coherent strategy and consult with Congress.”

Democrats did have plenty of concerns about what might follow these strikes. And if Trump wants to escalate involvement in Syria, foreign policy experts say he's going to need approval from Congress. (Some Democrats, like Sen. Tim Kaine (Va.), think Trump needed approval to do what he did Thursday night. In 2013, 98 House Republicans signed a letter warning Obama that he needed congressional approval if he wanted to launch military strikes in Syria.)

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The ongoing fight against the Islamic State in Syria could also color perceptions of the retaliation against Assad. Large majorities of the public have supported airstrikes targeting Islamic State insurgents, including 70 percent in 2014, and Trump might benefit from the perception that his action is connected to broader anti-terrorism efforts. Trump suggested such a connection in his statement announcing the attacks.

“Tonight, I call on all civilized nations to join us in seeking to end the slaughter and bloodshed in Syria, and also to end terrorism of all kinds and all types,” Trump said.

A final important factor is whether Friday's missile strike is an one-shot response to Assad's use of chemical weapons or whether it leads to broader military involvement. Hanging over Americans' 2013 resistance to action in Syria was the 2003 Iraq War, which was popular at the outset but became deeply unpopular after years of U.S. casualties and persistent challenges in establishing an effective state. And it seems that Trump's ability to avoid such a conflict is more important to the long-term popularity of his Syria policy and his presidency overall than immediate reactions to Friday's strike.

Amber Phillips contributed to this report.