When President Obama announced that the anti-Islamic State coalition had carried out airstrikes in Syria on Tuesday morning, he was quick to emphasize that the support of five Arab nations “makes it clear to the world that this is not America’s fight alone.” Jordan, Saudi Arabia, Bahrain, the United Arab Emirates, and Qatar participated in—or, in the latter case, at least supported—the U.S.-led airstrikes in Syria.

For Obama, participation from Arab allies was a necessity. This would not be another U.S. military intervention in the Middle East, but a cooperative, multilateral effort against a regional terror threat.

But what do the Arab nations get out of it?

For starters, each nation is domestically vulnerable to terrorist attacks, has a deep-rooted fear of a geopolitical situation favorable to Iran, and a longstanding policy of adhering to the U.S. foreign policy agenda in exchange for weapons and military protection. But there are differences, too. Here's a guide to the maze of motivations.

Jordan

Of the five coalition nations that assisted in Monday night’s airstrikes in Syria, Jordan is the only non-member of the Gulf Cooperation Council, and the only country that does not enjoy high revenue from energy exports. In other words, Jordon is not economically valuable to the U.S.

But it is strategically valuable. After backing Saddam Hussein’s losing side in the First Gulf War, Jordan made a decisive policy shift to seek U.S. support. In 1994, it became the second Arab state to sign a peace treaty with neighboring Israel, and also shares a border with Syria, Iraq, and Saudi Arabia. Today, Jordan serves as a buffer between Israel and several of its enemies and cooperates with the U.S. on counterterrorism.

In return, the U.S. pours economic and military aid into the country. Jordan is one of the highest recipients of U.S. foreign aid, getting $13.8 billion since 1951. In January, Jordan received $660 million in aid, with the stipulation that at least $340 million “be made available for the extraordinary costs related to instability in the region, including for security requirements along the border with Iraq.”

The U.S. has also committed 200 troops to help secure Jordan’s border with Syria. There are 600,000 Syrian refugees in Jordan and an estimated 1,800 Jordanians have made the opposite journey, traveling to Syria to fight alongside the Islamic State and the Al Qaeda-affiliated Jabhat Al-Nusra. The day after the coalition airstrikes, Jordanian King Abdullah II said that Islamic State militants pay their foreign fighters a $1,000 monthly salary—the equivalent to a hard-to-come-by middle-class job in Jordan.

King Abdullah II was one of the first leaders calling for Syrian President Bashar Al-Assad’s ouster and has hosted CIA paramilitary troops tasked with covertly training moderate Syrian rebels.

Saudi Arabia, Bahrain, and the United Arab Emirates

Though they have distinct foreign policy agendas, Saudi Arabia, Bahrain, and the UAE are bound by a shared fear of Shiite regional dominance, led by Iran. The Sunni leaders of these countries have funded and quietly supported extremist militant groups who fought against Iranian interests—in this case, Syrian opposition groups fighting Iranian-backed Assad and Hezbollah. Saudi Arabia has funneled weapons to opposition groups and has offered to host the U.S. military’s new program to train 5,000 rebels within the year. The UAE provides opposition groups with money to buy weapons or pay salaries to their soldiers. Bahrain, faced with its own uprising at home, has stayed out of direct intervention, but does not oppose the Gulf policy.

But support for these groups has the potential to backfire in the form of domestic attacks and international condemnation. Most of the September 11 hijackers were from Saudi Arabia and the UAE, and Al Qaeda in the Arabian Peninsula has actively tried to recruit and plan attacks in the Gulf. Since the September 11 attacks, the Gulf countries have emerged as some of the largest U.S. counterterrorism partners—despite continued support for violent non-state groups on both an individual and government level.

The three countries are heavily dependent on the U.S. for military support. Saudi Arabia purchases more weapons under the U.S. Foreign Military Sales program than any other state, with a current open case valued at $97 billion. The UAE has a small military of 51,000 personnel, and relies on the U.S. for air and missile defense training, fighter aircraft, and most recently, Predator drones. In 2002, Bahrain became a major non-NATO ally to the U.S., allowing it to purchase the same weapons as NATO member states.

The Gulf trio sees Iranian ambitions for regional dominance as the main source of instability in their neighborhood. They blame former Iraqi Prime Minister Nouri Al-Maliki’s policy of favoring Shiites for the current instability in Iraq, and the intervention by the Shiite militia Hezbollah on behalf of Assad for fueling the war in Syria. The rise of the Islamic State threatens to legitimize Assad’s claims that he and his allies are fighting radical terrorists. While the Sunni extremists of the Islamic State pose a definite threat to the Gulf countries, they fear Iran benefiting from the geopolitical chaos as much as they fear an Islamic State expansion.

The Gulf has long looked to the United States as a counterweight to Iranian supremacy in the Middle East, supporting efforts to sanction Iran and ramping up their own oil production to make up for the loss of Iranian fuel. They feared that the breakthrough November 2013 nuclear deal between Iran and the P5+1 would lead to a thawing of relations between the U.S. and their biggest rival. When the U.S. and Iran found themselves fighting the same terrorist group in Iraq and Syria, the Gulf bloc made a concerted effort to dissuade a U.S.-Iranian alliance and to ensure that defeating the Islamic State would not result in a victory for Iran, Assad, and Hezbollah.

Qatar

Early reports state that Qatar supported, but did not participate in, the airstrikes in Syria. Neither Qatari nor U.S. officials have provided a reason for their limited involvement, but with the smallest armed forces in the Middle East (less than 12,000 personnel), the small country rarely undertakes large military action, preferring to use soft power and diplomatic leverage.

Though a member of the GCC, Qatar routinely is at odds with other member states for its support to groups like the Muslim Brotherhood, Ennahda (the Muslim Brotherhood affiliate in Tunisia), and Hamas—Khaled Meshaal, Hamas political leader, currently works out of Doha. Qatar sees these groups as democracy-promoting freedom fighters; its Gulf neighbors view them as terrorist organizations that threaten the stability of established rulers. In March of this year, Saudi Arabia, the UAE, and Bahrain recalled their ambassadors to Qatar, saying Qatar failed to comply with the GCC policy of non-interference.

Without the support of the Gulf states that surround it, Qatar has leveraged its strategic location and massive wealth from natural gas reserves to build a strong alliance with the U.S. Once based in Saudi Arabia, the tactical headquarters for U.S. Central Command (CENTCOM) is now located at Qatar’s Al Udeid airbase near Doha. Qatar paid for the construction of the airbase and allows the U.S. to pre-position combat equipment there.

Qatar is one of the largest financiers of the Syrian opposition, and they are now being accused of either directly or indirectly supporting the Islamic State. Qatari foreign minister Khaled al-Attiyah denied these accusations last month. “We are repelled by their views, their violent methods and their ambitions,” he said, speaking about the Islamic State. “The vision of extremist groups for the region is one that we have not, nor will ever, support in any way.”

The truthfulness of the foreign minister’s statement is hard to assess. But lending active military support to a coalition committed to dropping bombs on Islamic State targets is a good way to maintain a strong relationship with the U.S. and hush criticisms from the Gulf.