It is a gulf Arab state that supports various Islamist groups - with critics saying it uses a TV channel as a tool of its foreign policy.

You could say that about a number of Arab countries, but it is Qatar that is being singled out for criticism and diplomatic ostracisation to a degree seldom seen before in the Arab world.

The reason? Qatar has long been out of line with the regional consensus and its neighbours believe this is the time to pull the small Gulf kingdom into line.

Other countries in the region may well support various Islamist militias in Syria.

Some sponsor TV channels perceived by many to have clearly biased agendas.

Saudi Arabia is accused of spending billions exporting a hardline form of Islam that its critics say leads to extremism.

But none of them share the sympathies and pet causes of Qatar.

It has provided a base for the leadership of Palestinian militant organisation Hamas, an offshoot of the Muslim Brotherhood which has long been a thorn in the side of Egypt's military dictatorship.

It has good relations with Hezbollah to the fury of most other Sunni Arab nations because of the Lebanese Shia militia's close ties with Shia theocratic regional power Iran.

Qatar defends these relations with diverse groups because it says there is considerable support for them among ordinary people across the Arab world.

But that cuts no ice with the elites who rule them.

Qatar-based TV channel Al Jazeera has long been an irritant for the undemocratic elites who run that world.

It was a scapegoat during the Arab Spring uprisings, its staff often the victims of intimidation and worse by repressive regimes fighting for survival during those revolutions.

And regimes across the Middle East have for a long time sought to take revenge.

Qatar has been cast out before.

But this is more severe and likely to be longer lasting.

Its regional rivals have found a common sense of purpose.

They are united in their fear of Iran and suspicion about Qatar's alleged ambivalence towards Tehran.

And they have been galvanised by US President Donald Trump's recent tour of the region.

Mr Trump challenged them to tackle extremists in their own backyards.

They have instead come down hard on a country they say is easy on extremists.

Previous administrations have taken a more nuanced, even-handed approach cultivating ties with as many countries as possible.

The Trump administration is being more blunt: stamp out extremism or else.

In that climate, Qatar's maverick foreign policy is more exposed.

Qatar has little leverage if the region remains united against it. The country houses a huge US military base, but it could be moved.

The diplomatic rupture is sending economic shockwaves across the region which will cause concern for all its governments - but Qatar is smaller and more vulnerable than its far richer, bigger neighbours and has more to fear from a protracted economic fallout.

It may choose to try and sit this one out as it has with previous moments of isolation, hoping the alliance ranged against it will begin to fracture, but it won't be able to for long.