What is Hamas?

Hamas means 'Zeal,' the Arabic acronym of the 'Islamic Resistance Movement'. Its aims are to restore Islamic rule to Palestine under the motto: 'Islam is the Solution.'

It refuses - and will continue to refuse - to recognise Israel, the Jewish-majority state which was established on 78% of historic Palestine and has held the remaining 22% - the Palestinian-majority West Bank and Gaza - under military occupation since 1967.

Who runs Hamas?

Blockade drains life from Gaza

The movement of goods into Gaza had been intermittent at best since Hamas won Palestinian elections early last year

Multimedia

• Pictures: Johnston is released

• Video: unarmed protester confronts gunman in Gaza

• Pictures: life in Gaza

BACKGROUND

• Israel continues Gaza blitz as 310 dead

• Q&A: Hamas and Gaza

• 97 days and counting for BBC's man in Gaza

• Now war is with the enemy within

• The little girl trapped by a quirk of war

The wider movement is run by its political bureau living in exile in Damascus, headed by Khaled Mashaal. Its internal power base is Gaza, historically poorer, more conservative, and more isolated than the much larger West Bank. After Israel assassinated its founder Sheikh Yassin in 2004 the most prominent figure has been Ismail Haniya, sacked as Prime Minister this week by President Mahmoud Abbas.

Its armed wing, the Izz al-din al-Qassam Brigades, has killed hundreds of Israelis in suicide bombings and shootings that Israel brands "terrorism" and Hamas insists is legitimate "resistance" against Israel's 40-year occupation.

What is Hamas's dispute with Fatah?

Secular Palestinian movements such as Fatah - founded by the late Yassir Arafat and his successor President Mahmoud Abbas - are as much an ideological obstacle as Israel to Hamas's ultimate goal of Islamising Palestine. Some Hamas hardliners privately speak with more venom about their internal foes - such as the Fatah strongman Mohammed Dahlan - than about Israelis.

For 15 years after Yassir Arafat's Fatah signed the historic Oslo Accords with Israel, Hamas were the rejectionist outsiders. When Hamas surprisingly won Palestinian parliamentary elections in 2006 Fatah turned the tables and undermined Hamas. The bitterness runs long and deep.

Why did Hamas win the 2006 election?

Where the outside world despaired of the peace process because many Palestinians voted for Hamas, many Palestinians voted for Hamas because they had already despaired of the peace process.

For years from pulpit, radio and newspaper, Hamas pushed the argument that Arafat got nothing in return for recognizing Israel - being denied a Palestinian state while Israel continued to build settlements in the occupied West Bank and Gaza.

Compounding this, the universal perception on the Palestinian street is that Fatah under Mr Arafat was an inept kleptocracy which whose leadership enriched itself at the expense of the Palestinian people by siphoning off western aid.

This perception was shrewdly exploited by Hamas, which temporarily toned down its hardline anti-Israel rhetoric during the election and presented itself as the 'clean' candidate under the platform 'Change and Reform.

Fatah ran an appalling campaign: late, complacent, poorly-organised and relying on vestigial loyalty to the fading memory of the late Mr Arafat. Dozens of sulking party elders also split the vote by standing as independents, letting Hamas through.

If Mr Abbas calls new elections, would Hamas win again?

That depends on when and why they are called. If they are seen as a coup against a democratically elected Hamas-led government at the instigation of the west – and Hamas will certainly spin it this way - Palestinians may vote Hamas again.

However many received a cold dose of realpolitik after seeing the US and Israeli lead a boycott of Hamas that turned them into pariahs for refusing to abandon violence and recognize Israel.

The early 'respect our democracy' defiance of ordinary Palestinians steadily gave way to pragmatism about the need for western aid, and anger at Hamas for perceived intransigence.

Secular Palestinians also fear that Hamas will impose veils, beards and sharia law on them.

Is Fatah finished?

It is unlikely that a 50-year-old movement that has long dominated the wider Palestine Liberation Organisation will simply fade away.

However it is riven by internal arguments between rival power brokers intent on seizing the reins after Mr Abbas.

Losing Gaza is a huge blow, but is only the latest in a series of historic defeats that has seen the PLO driven out of Jordan and Beirut.

Where does this leave Mr Abbas?

Considerably weakened, if not humiliated.

Many of his own armed cadres in the West Bank denounced him for dithering while Gaza burned. Throughout Thursday – the day Gaza fell– Fatah's leadership huddled in meetings in the West Bank capital Ramallah - more than 50 miles from Gaza City – while Fatah fighters waited for orders that never came until after the battle was lost.

Will Gaza split from the West Bank?

This would create a de facto three-state solution – Israel, an Islamist 'Hamastan' in Gaza and a more secular Fatah-dominated West Bank, where Hamas finds it far harder to operate with the powerful Israeli military's tanks, helicopters, checkpoints, roadblocks and snatch squads operating virtually everywhere.

Should the west continue to support Mr Abbas, or deal with Hamas?

Barring any unforeseen twists it is inconceivable that Israel or Washington will deal with an Islamist movement which refuses to recognise Israel .

For months Tony Blair has visited Ramallah speaking publicly of the need to reinforce the 'moderate' Mr Abbas.

But western money, guns and training are a two-edged sword for the Fatah leader. While enabling Palestinians to feed their families, they also make him appear a puppet of Jerusalem and Washington. It is now likely that many of those foreign weapons intended for Fatah have already fallen into the hands of Hamas.

The western policy of propping up secular moderates in the Middle East - 'Anyone but Allah' proxies to put it crudely - has a chequered modern history, to say the least. The Shah of Iran was swept away by Ayatollah Khomeini's followers and two years ago secular Iraqi parties heavily promoted by the west were routed by Shia Islamists.

Where does this leave the kidnapped BBC correspondent Alan Johnston?

Immediately after taking Gaza, Hamas ratcheted up pressure on Mr Johnston's suspected captors – a powerful Gaza clan - demanding that they released him immediately or face the consequences. It is unclear if they will take advantage of what is effectively a post-victory amnesty to free him, or if Hamas will follow through on its threats.

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