If Palestinians ever achieve the viable state to which they aspire, they will have a determined young Israeli activist to thank for its territory not being entirely swallowed by Israeli settlements.

Hagit Ofran, a former student of Jewish history, uses a four-wheel drive vehicle, pocket-sized camera, and a deep sense of mission to monitor the growth of Israeli settlements in the West Bank area captured during the 1967 Six Day War. Sometimes her findings make headlines well beyond Israel, translating into international pressure on the government to stop further encroachment on Palestinian land.

Ms. Ofran's official title is director of the Settlement Watch Team of the dovish Peace Now organization. In practice, she is a spy operating in hostile territory, snooping, sniffing, and piecing together bits of intelligence to gauge how much illicit building is going on.

On a recent scouting trip, Ofran spotted four new alabaster trailers spread like matchboxes on a hillside of the Alon settlement northeast of Jerusalem.

The prefabricated buildings are in effect helping to fragment the heartland of a future Palestine. ''It's not that one caravan will change the chances of Middle East peace,'' says Ofran. ''But another and another and another will determine whether we can have a two-state solution to the conflict or not.''

Israel's conservative government now faces a crucial decision over whether or not to extend a 10-month partial freeze on settlement building that expires in September. The Obama administration is pressing for the freeze to remain in place, but Prime Minister Benjamin Netanyahu's right-wing coalition partners want it scrapped to enable a wave of new building.

''If it is not extended then the freeze may have delayed a few hundred sites for months, but it will not have caused a real change,'' Ofran says.''If work is restarted it might mean that the chances of peace are doomed, at least with this government.''

A fluent Arabic speaker, Ofran sometimes is tipped off by Palestinians about new settler building. She pores over aerial photos commissioned by Peace Now, whose settlement watch unit is funded partly by the governments of Britain and Norway, and garners information from planning meetings and official documents.

In March, Ofran learned from the Jerusalem municipality's website that officials had given permits for settler building at the Shepherds Hotel site in East Jerusalem, which is predominantly Arab. She did not keep the information to herself – though she's tight-lipped about her exact role.

Embarrassingly for Prime Minister Benjamin Netanyahu, news of the new settlement project broke just before he was to meet President Obama at the White House, contributing to the frostiness of that encounter.

Danny Dayan, chairman of the Yesha Council that represents most of the half-million Israelis who have moved to the West Bank, accuses Ofran of serving foreign interests.

''In a democratic state it is legitimate to follow the settlements,'' Dayan says. ''The problem is that Peace Now does it with money that is from foreign sources, including from hostile sources. Her agenda is not objective.''

Ofran is up against a system that, although government-sponsored, lacks transparency. Much of its activity is illegal even according to Israeli law and settler leaders prefer to avoid public debate over it. Construction also violates the Geneva Convention and runs counter to international commitments Israel made to halt settlement building, for example in the 2003 international peace blueprint known as the road map. Tellingly, there is no distinct budget for building at settlements.

''The money is woven into a thousand other pieces of the budget. So you can't use the simple path of reading the budget to find out what's going on.'' says Israeli historian Gershom Gorenberg, author The Accidental Empire, a book about the origins of the settlements.

At any given moment, Ofran could be discovered and evicted from a settlement. There are a few settlements too dangerous for her to enter, she says. Her predecessor, Dror Etkes, had his vehicle stoned by residents of the hard-core Yizhar settlement near Nablus and Ofran does not venture there.

But after three years in the job, Ofran seems to have mastered the territory. She knows when it's appropriate to give a lift to hitch-hiking settler youths and when to avoid eye contact with settler guards.''If they recognize me here we are in trouble,'' she says, navigating a rocky road near the settlement of Maale Michmash. Although generally successful in keeping a low profile, Ofran's face is becoming better known because she is the subject of a new documentary film.

''I generally try not to make eye contact so there's less engagement and less chance they will recognize me. On the other hand, sometimes if you don't make eye contact it could be a problem because they'll know you're not from here.''

Ofran is the granddaughter of the late philosopher Yeshayahu Leibovich, one of the earliest Israeli critics of colonizing the West Bank after Israel's stunning victory in the 1967 Six Day war. He supported soldiers who refused to serve in the occupied territories and famously warned that those who did so risked becoming ''Judaeo-Nazis.''

''I used to hear him a lot and my character was influenced by his thinking.'' Ofran says

As her grandfather did, she believes Israel must withdraw from the West Bank and stop occupying its more than 2 million Palestinians if it is to remain a state with a predominantly Jewish population and character.

''I see myself first of all as Jewish and only then as an Israeli and it is very important to me how the Jewish state is acting,'' Ofran says. ''If we want to hold all the land than we must give the Palestinians full rights. So holding all the land means we will lose our independence as a Jewish people.''