Is the Gulf crisis undermining America's 'war on terror'?
The US considers all four countries to be allies. The Fifth Fleet docks in Bahrain, and Qatar hosts the Al-Udeid US airbase, a critical waystation in Washington's campaign against the Islamic State group.
For their part, Saudi Arabia and the UAE have assisted the US with operations against anti-American militants across the globe. Above all, though, the conflict will undermine American efforts to "combat terrorism financing" in the Gulf.
In June 2017, Bahrain, Saudi Arabia, the UAE and their allies in the Arab world imposed a blockade and severed relations with Qatar, after accusing it of supporting extremism and being too close to rival Iran, charges Doha vehemently denies.
Many observers viewed the Saudi-led bloc's diplomatic manoeuvre as specious: the monarchies' grievances have less to do with counterterrorism as the US envisions it, and more with regional geopolitical gripes.
|Many observers viewed the Saudi-led bloc's diplomatic manoeuvre as specious: the monarchies' grievances have less to do with counterterrorism as the US envisions it, and more with regional geopolitical gripes|
These include the Emirati-Qatari rivalry in the Libyan civil war and tensions between Qatar and Saudi Arabia over the Muslim Brotherhood - a transnational political movement seen by Saudi Arabia as an obstacle to political and religious hegemony in the Middle East.
Despite these differences, Bahrain, Qatar, Saudi Arabia and the UAE have all faced accusations of supporting anti-western militants and western-labelled "terrorist" organisations.
Saudi Arabia was still struggling to stop al-Qaeda and the Taliban from fundraising on its territory in 2011, 10 years after 9/11.
The Emiratis have faced accusations of bankrolling American-labelled terrorist organisations in Afghanistan and Pakistan, such as the Haqqani Network, Lashkar-e-Taiba, and al-Qaeda, which appears to have relied on Emirati banks to transfer funds used in the execution of 9/11.
In one incident, late Taliban leader Mullah Akhtar Mansour travelled to Bahrain once and Dubai 18 times to fundraise for the insurgents.
Saudi Arabia and the UAE backed the Taliban before 9/11, and the insurgents have maintained political contacts with both countries since then.
However universal these difficulties with terrorism financing, Qatar's high-profile actions in the Middle East have caught the attention of its allies and neighbours.
Qatar has provided the Taliban with a diplomatic mission in Doha, and Hamas - designated a "terrorist organisation" tied to the Muslim Brotherhood by some western nations - also has an office in the peninsula's capital.
Qatar's alleged 2017 payment of ransom for Qatari hostages held by Iranian-funded Iraqi militia Kataib Hizballah, which the US has labelled a terrorist organisation, provoked particular ire from Saudi Arabia and the UAE, two of Iran's chief rivals in the region. Qatar has consistently denied paying any such ransom.
Bahrain, meanwhile, blames Iran for a festering insurgency on its territory as well as protests that have buffeted Bahrain since the Arab Spring.
Underscoring the complexity of the dilemma, the US has sometimes relied on the Gulf monarchies as intermediaries with the anti-American militants over whom they have influence.
Qatar played a role in the 2014 release of Peter Theo Curtis, an American journalist held hostage by al-Qaeda's Syrian affiliate, and the Taliban's Doha-based diplomatic mission has functioned as ground zero for American negotiations with the insurgents, including discussions that led to the release of former Haqqani network hostage Bowe Bergdahl.
Saudi Arabia has also tried to use its clout to bring the Taliban to the negotiating table, an example of how Gulf monarchies play both sides.
|I have not seen any evidence to show that the ongoing spat has hindered or encumbered these states' ability to constrict terrorism finance|
Intra-Gulf tensions bode ill for the American-led effort to respond to terrorism financing in the Middle East.
In May 2017, a month before Saudi Arabia and the UAE launched their diplomatic offensive against Qatar, the US formed the Terrorist Financing Targeting Center, or TFTC, in cooperation with the six members of the Gulf Cooperation Council.
Though the TFTC has continued to issue sanctions, implementing the most recent in May, the ongoing conflict may limit its effectiveness.
Several observers have argued that the Gulf monarchies can prevent terrorist organisations from fundraising within their borders even amid headline-grabbing geopolitical disputes.
"I have not seen any evidence to show that the ongoing spat has hindered or encumbered these states' ability to constrict terrorism finance," said Dr Jonathan Schanzer.
The former terrorism financing analyst at the US Treasury, and Senior Vice President at the Foundation for Defense of Democracies also points out that: "These countries maintain sovereign programmes to monitor terror finance within their own borders."
Even if the Gulf monarchies dedicate resources to stemming terrorism financing on their own territory, another problem remains, namely that terrorism financing transcends borders.
During the height of the Syrian Civil War, Saudi fundraisers transferred their Syrian-bound donations through Kuwait, which has struggled to prevent money laundering on its territory in recent years.
Analysts have suggested that Bahrain, Saudi Arabia and the UAE compartmentalise their foreign policies until they find a resolution to their dispute with Qatar.
The Gulf monarchies could cooperate on their campaigns against money laundering by the Islamic State group and al-Qaeda, despite disagreements about topics such as the status of the Muslim Brotherhood, which Saudi Arabia and the UAE consider a terrorist organisation, but which the US has so far declined to label.
Despite their differences, all the Gulf monarchies want to maintain the US as their most important ally while keeping hostile American-designated terrorist organisations in check.
"I have long been critical of their ability to do so effectively - particularly Qatar and Kuwait - but I don't believe the spat has eroded their capabilities in any way," Dr Schanzer told The New Arab. "It remains a question of national will for all the Gulf states. And that will is often lacking."
Austin Bodetti is a freelance journalist focusing on conflict in the greater Middle East.
He has reported from Indonesia, Iraq, Myanmar, South Sudan and Thailand, and his writing has appeared in Motherboard, The Daily Beast, USA Today, Vox, Wired, and Yahoo News.