Hamas is the largest and most influential Palestinian militant movement. In January 2006, the group won the Palestinian Authority's (PA) general legislative elections, defeating Fatah, the party of the PA's president, Mahmoud Abbas, and setting the stage for a power struggle. Since attaining power, Hamas has continued its refusal to recognize the state of Israel, leading to crippling economic sanctions. Historically, Hamas has sponsored an extensive social service network. The group has also operated a terrorist wing, carrying out suicide bombings and attacks using mortars and short-range rockets. Hamas has launched attacks both in the Palestinian territories of the West Bank and Gaza Strip, and inside the pre-1967 boundaries of Israel. In Arabic, the word "hamas" means zeal. But it's also an Arabic acronym for "Harakat al-Muqawama al-Islamiya," or Islamic Resistance Movement.

Hamas grew out of the Muslim Brotherhood, a religious and political organization founded in Egypt with branches throughout the Arab world. Beginning in the late 1960s, Hamas's founder and spiritual leader, Sheikh Ahmed Yassin, preached and did charitable work in the West Bank and Gaza Strip, both of which were occupied by Israel following the 1967 Six-Day War. In 1973, Yassin established al-Mujamma' al-Islami (the Islamic Center) to coordinate the Muslim Brotherhood's political activities in Gaza. Yassin founded Hamas as the Muslim Brotherhood's local political arm in December 1987, following the eruption of the first intifada, a Palestinian uprising against Israeli control of the West Bank and Gaza. Hamas published its official charter in 1988, moving decidedly away from the Muslim Brotherhood's ethos of nonviolence.

The first Hamas suicide bombing took place in April 1993. Five months later, Yasir Arafat, then the leader of the Palestine Liberation Organization (PLO), and Yitzhak Rabin, then-prime minister of Israel, sealed the Oslo accords�an Israeli-Palestinian peace pact that eventually unraveled. Rabin was assassinated by an Israeli right-wing fanatic in November 1995. Arafat died in November 2004.

Since its victory in the 2006 Palestinian legislative elections, Hamas has failed to unify around a coherent program,�exacerbating tensions within the Palestinian Authority.�Ismail Haniyeh, the Hamas�prime minister and senior Hamas figure in Gaza, has appeared at odds with Khaled Meshal, Hamas�s overall leader who lives in Syrian exile. A Backgrounder profiles these and other Hamas leaders.

Historically, Hamas has operated as an opposition group in Gaza, the West Bank, and inside Israel. Most of the population of Gaza and the West Bank is officially ruled by the Palestinian Authority government, so Hamas� new role as the legislature�s controlling party has forced the group to reconsider the function and scope of its operations. For instance, since�taking power in 2006, Hamas leaders have embarked on several diplomatic visits throughout the region. Early on, some observers hoped that political legitimacy�and the accountability that comes with it�could�wean Hamas away from violence. But to date, the group has refused to eschew violence and remains adamant about reversing�the decision by its rival faction, the more secular Fatah movement, to recognize Israel's right to exist.�In the summer of 2007, Hamas tensions with the Palestinian President Mahmoud Abbas, a Fatah man, came to a head and Hamas routed Fatah supporters, killing many and sending others fleeing to the West Bank. The result was a de facto geographic division of Palestinian-held territory, with�Hamas holding sway in Gaza and�Fatah maintaining the internationally recognized Palestinian Authority government in the�West Bank town of Ramallah.�Egyptian efforts to reconcile the two factions have come to nothing.

Since coming to power in Gaza, rockets fired from the Hamas enclave have consistently landed on�Israeli cities near the border, sometimes producing casualties. Israel consistently alleged that Iranian and other weapons were being smuggled into Gaza through a series of tunnels, and with Egypt maintained tight control on the enclaves borders. International aid agencies say this led to severe shortages.�A six-month ceasefire�calmed things somewhat in 2008, but�toward the end of the year,�Hamas called off the truce and�resumed firing rockets into Israel. The response was an air assault in late December and, in the first week of 2009, a full blown Israeli invasion of the territory.

Hamas combines Palestinian nationalism with Islamic fundamentalism. Its founding charter commits the group to the destruction of Israel, the replacement of the PA with an Islamist state on the West Bank and Gaza, and to raising "the banner of Allah over every inch of Palestine." Its leaders have called suicide attacks the "F-16" of the Palestinian people. In July 2009, Khaled Meshaal said Hamas was willing to cooperate with the United States (WSJ) on promoting a resolution to the Arab-Israeli conflict. Hamas, he said, would accept a Palestinian state based on 1967 borders provided Palestinian refugees be allowed to return to Israel and East Jerusalem be recognized as the Palestinian capital. The proposal fell short of recognizing the state of Israel, a necessary step for Hamas to be included in peace talks.

No. In addition to its military wing, the so-called Izz al-Din al-Qassam Brigade, Hamas devotes much of its estimated $70-million annual budget to an extensive social services network. Indeed, the extensive social and political work done by Hamas - and its reputation among Palestinians as averse to corruption - partly explain its defeat of the Fatah old guard in the 2006 legislative vote. Hamas�funds schools, orphanages, mosques, healthcare clinics, soup kitchens, and sports leagues. "Approximately 90 percent of its work is in social, welfare, cultural, and educational activities," writes the Israeli scholar Reuven Paz. The Palestinian Authority often fails to provide such services, and Hamas's efforts in this area�as well as a reputation for honesty, in contrast to the many Fatah officials accused of corruption�help to explain the broad popularity it summoned to defeat Fatah in the PA's recent elections.

Hamas�s military wing is believed to have more than one thousand active members and thousands of supporters and sympathizers. On March 22, 2004, more than two hundred thousand Palestinians are estimated to have marched in Yassin�s funeral. On April 18, 2004, a similar number publicly mourned the death of Rantisi.

Since its electoral victory to lead the PA, Hamas has had public funds at its disposal, though it does not have access to the foreign-aid dollars traditionally provided by the United States and European Union to the PA. Historically, much of Hamas's funding came from Palestinian expatriates and private donors in Saudi Arabia and other oil-rich Persian Gulf states. Iran also provides significant support, which some diplomats say could amount to $20 million to $30 million per year. In addition, some Muslim charities in the United States, Canada, and Western Europe funnel money into Hamas-backed social service groups. In December 2001, the Bush administration seized the assets of the Holy Land Foundation, the largest Muslim charity in the United States, on suspicions it was funding Hamas.

Hamas is believed to have killed more than five hundred people in more than 350 separate terrorist attacks since 1993. Not all Hamas's attacks have been carried out by suicide bombers. The group has also accepted responsibility for assaults using mortars, short-range rockets, and small arms fire. In 1996, Hamas bombings played an important role in undermining the election hopes of Labor Party leader Shimon Peres, who represented the succession to assassinated Oslo Accords signatory, Yitzhak Rabin. (Likud's Benjamin Netanyahu, who ran against the accords, won instead). Between 2001 and 2003, in particular,�Hamas and its comrades of Palestinian Islamic Jihad carried out dozens of such attacks, ultimately leading Israel to begin construction of a barrier between itself and Palestinian regions.

The organization generally targets deeply religious young men�although some bombers have been older. The recruits do not fit the usual psychological profile of suicidal people, who are often desperate or clinically depressed. Hamas bombers often hold paying jobs, even in poverty-stricken Gaza. What they have in common, studies say, is an intense hatred of Israel. After a bombing, Hamas gives the family of the suicide bomber between three thousand dollars and five thousand dollars and assures them their son died a martyr in holy jihad.

The recruits undergo intense religious indoctrination, attend lectures, and undertake long fasts. The week before the bombing, the volunteers are watched closely by two Hamas activists for any signs of wavering, according to Nasra Hassan, writing in the New Yorker. Shortly before the "sacred explosion," as Hamas calls it, the bomber records a video testament. To draw inspiration, he repeatedly watches his video and those made by his predecessors and then sets off for his would-be martyrdom after performing a ritual ablution and donning clean clothes. Hamas clerics assure the bombers their deaths will be painless and that dozens of virgins await them in paradise. The average bombing costs about $150.

According to Palestinian pollster Khalil Shikaki, in late 2006 Hamas still enjoyed public backing, though most Palestinians also wanted to see a negotiated settlement with Israel. According to Lt. Gen. Keith Dayton, the U.S. security coordinator for Israel and the Palestinian Territories, brutal internal clashes in Gaza have caused Hamas to lose some goodwill among Palestinians. In fact, the group has a history of fluctuating approval: Following the collapse of the peace process in the late 1990s, Hamas� popularity rose as Arafat�s fell. In the spring of 2002, during a period of intensified armed conflict between Israeli security forces and Hamas militants, polls showed that Arafat's Fatah faction of the PLO and the Islamists each commanded support from roughly 30 percent of Palestinians in the West Bank and Gaza (the remaining Palestinians were either independent, undecided, or supported other factions). But trust in Hamas reportedly dropped in 2004. In a poll conducted by the Jerusalem Media and Communication Center (JMCC) after Arafat's death, 18.6 percent of Palestinians named Hamas as the Palestinian faction they most trusted, down from 23 percent a year earlier. Hamas experienced a short-lived spike in popularity after the Israeli withdrawal from Gaza in August 2005; after a rocket explosion at a Hamas rally September 23, 2005, killed fifteen people, Hamas blamed Israel and launched rocket attacks against it. Israel retaliated with punitive air strikes, which Palestinians blamed Hamas for provoking. The explosion was revealed to be an accident. In late 2008 and early 2009, during another violent flare up which resulted in Israeli land raids into the Gaza Strip, several news agencies reported that Hamas' popularity had stayed constant or even increased. By the end of June, public support for Hamas in the West Bank and Gaza Strip fell again to 18.8 percent, according to recent JMCC polls.

No. Hamas boycotted the January 2005 PA presidential elections. But even prior to its 2006 victory in the PA's legislative elections, the group had made strong showings in municipal elections, especially in Gaza. In December 2004 West Bank local elections, Fatah won 135 seats and Hamas won seventy-five. In Gaza, where Hamas is based, it won seventy-seven out of 118 seats in ten council elections held in January 2005. Hamas appeared to have lost its political momentum in a September 2005 round of local elections in the West Bank: Fatah, benefiting from the Israeli withdrawal, took 54 percent of the vote over Hamas� 26 percent.