JERUSALEM A maze of violent fault lines runs across Israel and the Palestinian territories, but the past year has been relatively calm. Here is a look at where violence may flare up in 2009 and the factors to watch:
ISRAEL VS HAMAS, GAZA STRIP
The bloodiest arena this year. Some 500 people were killed, mostly Palestinians, 120 of them in one week in early March. An Egyptian-brokered truce has dampened violence since June but Hamas says it expires on December 19 -- though that would not necessarily mean a full or immediate resumption of fighting.
The Islamists, who won a 2006 parliamentary election but are shunned by Israel for refusing to renounce violence, seem set on consolidating control of Gaza, won in 2007 in a fight with President Mahmoud Abbas's secular Fatah faction. Hamas sees its support dependent on maintaining pressure on Israel, such as with improvised rockets, but seems wary of provoking an all-out Israeli offensive or heavy strikes targeting its leadership.
In Israel, much may depend on a February 10 election, though both Tzipi Livni's centrist Kadima and Benjamin Netanyahu's right-wing Likud need to show voters they can curb Hamas. The lame-duck Prime Minister Ehud Olmert seems unlikely to mount a major offensive before the election, though a randomly bloody Palestinian rocket strike -- say, on a school -- could force Israel's hand into launching some sort of punitive action.
Longer-term over the year, since Olmert's 2006 Lebanon war no Israeli leader relishes the prospect of heavy army casualties from invading Gaza. Netanyahu aides have indicated he favors strikes on the Hamas leadership rather than a mass assault.
FATAH VS HAMAS, GAZA STRIP
Fatah seems leaderless and powerless in the enclave. Hamas blamed Fatah for a spate of bombing attacks against its men this year, but whatever the cause, it did little to upset Hamas. Barring a rout of Hamas and its leaders in some so far unlikely Israeli invasion, Fatah's Gaza fortunes seem bleak.
HAMAS VS FATAH, WEST BANK
One of the great unknowns. Hamas has strong support in the West Bank. But the Israeli occupying forces are not going to let it seize control there as easily as it routed Abbas's forces in Gaza. Nonetheless, Hamas could launch new armed attacks on Israeli troops and settlers, drawing crackdowns by Israel and by Abbas's forces that would hurt Fatah prestige in the eyes of many Palestinians. An early test of the depth of Hamas-Fatah tensions will come in January, when Abbas is set to presidential and parliamentary elections -- votes from which Hamas is likely to be barred, and which the Islamists would not hold in Gaza.
ISRAEL VS SETTLERS, WEST BANK
Some hardline Jewish settlers have recently stepped up attacks on Palestinians as well as on Israeli security forces in an apparent bid to thwart prospects of reaching any peace accord under which their enclaves would be shut down. Should Palestinians be killed by settlers, it could generate pressure on Abbas to abandon negotiations with Israel and to push Israel harder to act against settlers. Should Israel respond to such bloodshed with a crackdown on settlers, it could restore momentum to the diplomatic process. For many Israelis, a lethal settler attack on the army would be an unprecedented, watershed event that could shake public support for the ultranationalists.
HAMAS VS ISRAEL, ISRAEL
Could Hamas take the fight into Israel, maybe in retaliation for a major assault on Gaza, as it did in 2000-2004 when 500 people were killed in wave of suicide bombings on Israeli buses, cafes and other sites? Barriers around Gaza and the West Bank impede access for militants. Hamas may not wish to provoke threatened Israeli assassination campaigns against its leaders.
FATAH VS ISRAEL, ISRAEL
After more than 15 years of peace negotiations born of the Oslo Accords of 1993 which brought Yasser Arafat's PLO home from exile, the Abbas administration is pressing ahead with talks despite widespread Palestinian doubts over the prospects of a final accord. As Abbas is beholden to foreign powers which fund and train his security forces, an armed confrontation between the interim Palestinian Authority and Israel is highly unlikely. The focus of conflict seems to remain fellow Palestinians.
(Reporting by Alastair Macdonald, Dan Williams, Nidal al-Mughrabi, Joseph Nasr and Wafa Amr; Editing by Samia Nakhoul)