Ramallah/Gaza - Hamas currently finds itself fighting the Israelis in the Gaza Strip, but the Islamist movement could soon find itself caught up in another battle, this one with its fierce rival, the secular Fatah party of President Mahmoud Abbas.

Abbas' four-year term as President is due to end on January 8. His aides, counting on an amendment that has not been ratified, insist he can remain in office for an additional year, in order to to hold legislative and presidential elections together.

Not so, says Hamas, demanding that Abbas step down on the appointed date so its top-ranking legislator, Palestinian Legislative Council Speaker Aziz Dweik, can serve as transitional president for 60 days, as the law requires.

Dweik, however, is currently serving three years in an Israel jail, and the Israelis are unlikely to let him out so that Abbas, their main peace partner, can be replaced as president - even temporarily - by the representative of a movement which denies the Jewish state's right to exist.

But while Hamas has said it will declare Dweik the new acting President, this was before the movement got embroiled in a vicious fight with Israel which currently sees its leaders in the Gaza Strip in hiding.

Some Palestinians think that Hamas' current troubles will prevent it from going ahead and declaring Dweik president, even if this would be a huge step in its ambition of becoming the main representative of the Palestinian people.

To bolster this theory, they say that such a move by Hamas would not only divert attention from the current fight against the Israelis in Gaza, but widen the already bitter rift between the two rivals at a time Hamas needs Palestinian unity and backing in its fight against the Israelis.

Relations between the two movements have been strained, sometimes violently so, since Hamas defeated Fatah in the January 2006 elections. The tensions boiled over in June 2007, when Hamas gunmen routed police officers loyal to Abbas and Fatah to seize control of the Gaza Strip.

In addition, going against Abbas would also enrage moderate Arab states, most prominently Egypt, which at this point the beleaguered Islamist movement cannot afford to alienate even more than it did by not showing up in Cairo in November for unity talks with Fatah, and by rejecting Cairo's structures to renew a truce with Israel.

Another disadvantage is that a humiliated Abbas might be less determined in his efforts to bring about a truce between Israel and Hamas.

On the other hand, a Hamas announcement that its candidate has replaced Abbas would serve to remind the Palestinian public and the world at large that despite the battering it has taken from the Israelis, the movement is still a force to be reckoned with, still a player who cannot be sidelined.

It would also restore to Hamas some of the prestige it has lost, not just by the incessant Israeli assault which has destroyed virtually all its installations in the Strip and driven its leaders underground, but at the hands of Egypt, which has minced no words in blaming the Islamic movement for the current crisis.

It would help the movement claim victory in its current fight against the Israelis by allowing it to claim that not only has it remained steadfast steadfast in the face of the Israel onslaught, but has emerged as the force now speaking for the Palestinian Authority.

The question is whether Hamas leaders think the benefits of "ousting" Abbas outweigh the pitfalls, and the answer to that will be known until January 9.