Most foreign policy entanglements do not result in a “rally around the flag” event — when a president’s popularity jumps because Americans rally behind their commander-in-chief. That’s according to a 2001 study by William Baker of the Arkansas School for Mathematics and Sciences and John Oneal of the University of Alabama. Their study found that only 39 percent of U.S. military interventions from 1933 to 1993 resulted in a rise in the president’s approval rating. Still, 39 percent is a sizable minority of the time. So, will President Trump’s order to launch missiles at a Syrian airfield be one of them?

After former President Barack Obama laid out a four-point plan to go after the Islamic State group in 2014, I described five characteristics of foreign policy interventions that tend to increase the chances of a rally-around-the-flag effect. The list, compiled from political science papers, isn’t comprehensive, but it provides a good blueprint: The more points an intervention hits, the more likely the president’s approval rating will increase. Let’s take them one at a time.

1. Americans tend to react with greater enthusiasm when there is bipartisan support for an intervention.

Trump’s actions have broad support in Congress, including from Democrats like Nancy Pelosi and Chuck Schumer and stronger approval from Republicans like John McCain and Mitch McConnell. So the airstrike probably meets this criteria. Bipartisanship on Syria is nothing new. When Congress voted on arming the Syrian rebels in 2014, party affiliation was not a great predictor of support. Of course, then, like now, there were intraparty divisions on Syria — within the GOP, for example, libertarian-leaning officials such as Rand Paul were advocates for a less interventionist policy. At the same time, while there may be bipartisan support for the airstrike in Washington, it’s not clear that there will be bipartisan support among Americans. A Gallup poll taken in February 2016, during the final year of the Obama administration, found a fairly equally breakdown among those who wanted U.S. involvement in Syria to increase, stay steady or drop. But opinions can shift over time — especially with a new president of a different party from the previous one. Polls may end up showing that the public — Democrats and Republicans — backs the limited actions Trump has taken so far, but if the U.S. role expands, that’s less likely to be true.

That speaks to a larger point: What comes next in Syria may be more important than what Trump has done so far in terms of how his actions are viewed. To oversimplify: Military interventions in the Middle East can go bad in a hurry.

2. Americans tend to give the president a boost when he’s acting against a major power.

Most people would not define Syria as a major power. It’s a small country in the Middle East mired in a long, tragic civil war. Yet, Syria is also a proxy for other, more powerful countries. Iran is a big backer of the Assad government. Perhaps even more importantly, Russia is also deeply involved in the conflict and allied with Bashar Assad. (The Russian government reacted very negatively to the U.S. airstrike.) The Trump administration is also looking into whether or not Russia, itself, was involved in the chemical attack. If the public comes to see the Syria strike as a move against Russia and/or Iran as much as against Assad, it may be more likely to rally behind Trump.

3. Americans seem to respond more positively when the U.N. Security Council gives its approval to a foreign endeavor.

This is a clear no. Russia is on the Security Council and definitely does not approve of the U.S. strike. It doesn’t even see a need for a resolution disapproving of the chemical weapons attack. That said, most other nations on the Security Council deplored the chemical attack. It’s plausible that Americans will hear those other countries speaking out against the attack and make the judgment that Trump’s actions have broad, global support. It’s also possible that Americans don’t really care too much about U.N. approval anymore and that this point is an artifact of a previous era. Just 37 percent of Americans think the U.N. is doing a good job solving the problems it faces, according to Gallup.

4. Americans are more likely to warm toward the president when there are revisionist goals at stake.

Revisionist goals are generally defined as “making claims to territory,” “attempting to overthrow a regime” or “declaring the intention not to abide by another state’s policy.” The U.S. isn’t trying to claim territory in the Syrian conflict, as it did during wars in Afghanistan and Iraq. Nor is it clear whether the White House is seeking to remove Assad from power. The U.S. is, however, trying to change Assad’s policy on chemical weapons. Further, as stated earlier, the Syrian conflict has multiple actors, including Islamic State, which the U.S. certainly wants to overthrow. The Islamic State, however, was not a target in the U.S. missile strike. If the White House pivots and frames any U.S. action in Syria as about the conflict at large, there’s a greater chance that Trump’s actions will be seen as combating revisionist goals.

5. Americans are more likely to rally behind a president at the beginning of his presidency.

Trump is less than 100 days into his presidency, so this factor should work in his favor. Unlike other presidents, though, Trump has quickly built up a lot of dislike among independents and members of the opposing party. New presidents tend to get the benefit of the doubt — that’s why this point is on our list — but Trump is not your average new president. If Democratic and some independent voters are already beyond his reach (and his high “strongly disapprove” job rating numbers suggests they may be), it may not matter that we’re early in the Trump presidency.

When you take all these points into account, it’s not clear what will happen to Trump’s approval rating in the coming days and weeks. Although few of these are slam dunks in either direction, two are likely to result in a bump (points No. 1 and No. 5), one probably won’t (No. 3) — and two aren’t clear (No. 2 and No. 4). If you’re looking for some tiebreakers, Baker and Oneal’s study found that the average foreign policy entanglement results in an approval rating jump of just 0.1 percentage points. And during the Obama administration, the only event that produced any rally-around-the-flag effect was the killing of Osama bin Laden. And that effect lasted just a month.

One thing to keep an eye on going forward is whether the conflict in Syria, and U.S. involvement, escalates. As I noted earlier, that may ultimately determine where public opinion falls. Studies, not surprisingly, show the American people are less likely to support Trump’s policies if there are U.S. casualties — whatever they think of Trump’s initial airstrike.