This is the worst diplomatic crisis in the Gulf region in decades.
On June 5, Saudi Arabia, United Arab Emirates, Bahrain and Egypt decided to break off ties with Qatar, accusing the Gulf state of supporting terrorism and of destabilising the whole region.
On May 24, Emir Sheikh Tamim bin Hamad Al Thani, the ruler of Qatar, allegedly criticised the US-Saudi move and described Iran as an "Islamic power". The Qatar News Agency quoted the emir as saying, "There is no wisdom in harbouring hostility towards Iran". This infuriated Saudi Arabia and the UAE.
Qatar then questioned the veracity of the comments and said its news agency was hacked. Nevertheless, the diplomatic rift been deepening, culminating in the current crisis.
Not the first diplomatic imbroglio
This is not the first time that Qatar, a thumb-shaped emirate of the size of the US state of Connecticut, has become embroiled a diplomatic imbroglio with its Gulf Cooperation Council (GCC) partners Bahrain, Saudi Arabia and the UAE.
These three Gulf Arab states withdrew their ambassadors from Qatar's capital Doha in early 2014, on the pretext that the country had links to the Muslim Brotherhood and gave refuge to its leaders after the fall of Egypt's first democratically elected government in July 2013.
Saudi Arabia declared the Muslim Brotherhood, which it views as an alternative source of authority that's opposed to hereditary monarchical rule, a terrorist organisation in early March 2014.
But the current crisis is much more serious than the 2014 diplomatic spat, which was resolved after eight months, with Saudi, Emirati and Bahraini ambassadors returning to Doha in November of the same year on the condition that Qatar would never allow the Muslim Brotherhood to operate from its territory.
Iran in the centre
Unlike the 2014 crisis, the current Qatari-Saudi rift is not just an intra-GCC falling out, as it involves Saudi Arabia's regional rival Iran.
Qatar is seen by the Saudi government and its Emirati and Bahraini counterparts as a spoiler of efforts to forge a unified Arab-Muslim position, undergirded by the Trump administration, against Iran's so-called "terrorist agenda" in Arab countries.
A week before US President Donald Trump visited Riyadh to consolidate the anti-Iran alliance, the Saudi arabic-language daily newspaper Okaz reported a secret meeting between the Qatari Foreign Minister Sheikh Mohammad Bin Abdul Rahman Al Thani, who was officially visiting Baghdad at the time, and the Iranian Quds Force Commander Qasim Sulaimani.
The newspaper accused Qatar of exiting "early from the Arab-Islamic consensus" on Iran, adding "its defence of the Iranian terrorist regime shows the secret Doha-Tehran alliance intends to strike at Arab and Islamic solidarity."
All of this while Qatar signed the anti-Iran Riyadh Declaration issued after the Arab-Islamic-America summit on May 21 2017.
But why would Qatar, a country that hosts the largest US air force base in the Middle East (Al-Udeid), veer off the Saudi-led GCC military and diplomatic track?
Gulf watchers know that Qatar is suspicious of Saudi goals under the GCC umbrella, and it wants an independent foreign policy, free from Saudi or Iranian influence.
Qatar hardly sees Saudi Arabia as a harmless neighbour. Tensions in Saudi-Qatar relations started right after the former emir Sheikh Hamad Bin Khaifa Al Thani (1995 - 2013) came to power via a bloodless coup in 1995 by overthrowing his father Sheikh Khalifa Bin Hamad Al Thani. Sheikh Khalifa was visiting Saudi Arabia at the time, which embarrassed the Saudi government.
Sheikh Hamad's takeover in 1995 was preceded by a Saudi attack on a Qatari border security post in September 1992, in violation of a mutual defence treaty the two states had signed in 1982.
Riyadh also thwarted Qatari initiatives to export liquefied gas to other GCC member states in the 1990s. Emir Sheikh Hamad began to pull Qatar out of the Saudi shadow, a policy that Emir Sheikh Tamim is also pursuing.
Qatari satellite news channel Al Jazeera occasionally broadcasts programs criticising Saudi Arabia and, much to the anger of Riyadh, it hosted Saudi dissidents in a popular talk show in June 2002.
The incident led to Saudi Arabia recalling its ambassador from Doha in September 2002. Full diplomatic relations between the two countries were restored five years later, in September 2007, on Qatari assurance that Al Jazeera would refrain from broadcasting anti-Saudi programs.
A big push in the region
At the same time, Qatar, with the massive amount of oil and gas-generated income in its coffers (US$191 billion GDP in 2012), has been pushing for a bigger foreign policy and diplomatic profile in the region.
Doha successfully mediated a series of conflicts in the 2000s. It broke the political impasse in Lebanon by persuading the Sunni-led Lebanese government and the opposition Hezbollah to sign the May 2008 Doha Agreement; it mediated the conflict between the Yemeni government and Houthis in February 2008 (though it failed subsequently to find a permanent solution to the conflict); and, in February 2010, it facilitated a ceasefire agreement between the Sudanese government and the opposition Justice and Equality Movement.
These successful mediations brought the tiny country enviable diplomatic plaudits from home and abroad.
In 2011, to the surprise of many regional states, the Qatar military participated in the NATO-led intervention to dislodge the Gaddafi government in Libya. It wanted to achieve a similar goal in Syria - to topple the Bashar Al-Assad government - but did not succeed primarily due to Iranian and Russian opposition.
Despite being an autocracy, Qatar presented itself as a frontline Arab state for politically transforming the Arab world, under the rubric of the Arab Spring movements.
Its objective was to strengthen Qatari national security and foreign policy autonomy in the Gulf region, a neighbourhood dominated by giants such as Iran and Saudi Arabia.
Nonetheless, the diplomatic spat with Saudi Arabia does not bode well for Qatar. The Saudi-led diplomatic offensive has isolated it from the rest of GCC and the Middle East region by cutting off air, land and sea routes to Doha.
Doha has been accused again of supporting regional terror groups - al-Qaeda and ISIL in Iraq and Syria - and cooperating with Iran.
Qatar has always denied funding extremist groups, but the small country has been accused in the last few years of allowing terrorist financiers to operate within its territory with impunity.
The Qatari government has also pledged support for Hamas, the Palestinian group regarded as a liberation force against Israeli occupation by most Muslim countries, but as a terrorist organisation by the United States, Israel, Egypt and Canada.
Qatar can expect no serious help from Iran either, as any possible Iranian political or diplomatic help runs the risk of further embittering Saudi-Qatar relations and permanently subject Doha to Saudi wrath.
The Trump administration is definitely not on Qatar's side, as Secretary of State Rex Tillerson, speaking in Australia, indirectly hoped to resolve the intra-GCC irritants and put Qatar back in the Saudi-driven GCC orbit.
Cracks in the Saudi-Qatar relationship would undercut the joint Arab-US fight against regional terror and extremist groups. It's difficult to say how long Qatar would be in the position to resist the Saudi diplomatic offensive.
But backing down from the fight with Riyadh looks set to produce two outcomes. First, Doha would be obliged to downgrade its support to rebel groups in Syria, linked to either Muslim Brotherhood or al-Qaeda. And second, it must be willing to shed some degree of its foreign policy autonomy to participate in the Saudi-led offensive against Iran.
In either case, Qatar has undermined the anti-Iran alliance, giving Tehran more time to reassess the situation and consider its options.