Israel's ultra-Orthodox community, easily identified by their distinct black-and-white clothing, has traditionally voted as a bloc, but is increasingly looking across the spectrum to non-Orthodox parties.
Ahead of January 22 elections, its two main parties are campaigning hard, hoping to protect and maybe even increase the 15 seats they hold in the outgoing government of Prime Minister Benjamin Netanyahu.
Ten of those belong to the ultra-Orthodox Shas party, which traditionally represents Sephardic Jews -- those of Middle Eastern origin -- and five belong to United Torah Judaism (UTJ), which represents Ashkenazi, or European ultra-Orthodox.
Topping the agenda is preventing the next government from passing legislation that would force the ultra-Orthodox to serve in the army.
The issue is a key priority for Avigdor Lieberman, the former foreign minister whose hardline secular nationalist Yisrael Beitenu is running on a joint list with Netanyahu's rightwing Likud.
The ultra-Orthodox are firmly opposed to mandatory service, with Shas's spiritual guide Rabbi Ovadia Yosef even threatening he would advise his flock to leave Israel if a law mandating military service was passed.
Until last year, a law was in force which allowed tens of thousands of ultra-Orthodox men to avoid being drafted by enrolling in religious seminaries called yeshivas.
Originally intended as a way to allow them to defer their time serving in the military or doing national service, the so-called Tal Law was struck down last year by the High Court, which said it had failed in its purpose.
The government has pledged to push through new legislation, prompting widespread concern among the ultra-Orthodox that they will be forced to enlist.
"Some people are reluctant to vote and they will be responsible for the war which will break out here when the secular authorities force yeshiva students to join the army," warned Yisrael Eichler, UTJ's number two.
The two parties also face other challenges.
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A traditional defender of the poor, Shas was part of a government which failed to keep a lid on the price of basic goods, which have soared in recent years, contributing to social unrest.
That could send some of Shas's constituents into the arms of Labour, which has focused its platform on the economic discontent that spawned massive demonstrations in the summer of 2011.
Others could swing towards the hardline national religious Jewish Home, which combines religious values with a pledge to make Israeli society fairer for all.
The ultra-Orthodox number around 900,000, making up a sixth of Israel's population, but only around half of them are old enough to vote.
There are also thousands who boycott elections because their strict religious beliefs include opposition to Zionism and the state of Israel.
Meny Schwartz, who heads the ultra-Orthodox Kol Haredi radio station, says that many no longer feel constrained to vote for Shas and UTJ.
"A large part of the ultra-Orthodox population no longer vote for those parties, for a variety of reasons," he told AFP.
"Some believe it is forbidden to vote for anti-Zionist reasons; others who are disappointed by the leadership of the ultra-Orthodox parties, no longer vote, or vote for parties like Likud or parties further to the right," he said.
The ultra-Orthodox parties have in turn broadened their electoral campaigns, hoping to attract the secular working class by touting social justice.
UTJ leader and deputy health minister Yaakov Litzman can point to a policy extending free dental care to children under 12.
And Shas, which controls the housing ministry, is flagging up the thousands of houses built throughout the country in the last four years.
But their political future rests in the hands of Netanyahu, who is widely expected to lead the joint Likud-Beitenu list to a commanding victory.
He could choose to form a rightwing coalition with the ultra-Orthodox and Jewish Home, but could also join forces with centrist parties like HaTnuah and Yesh Atid.