By Dan Williams
JERUSALEM, March 14 (Reuters) - Flagging in opinion polls before Tuesday's election in Israel, Prime Minister Benjamin Netanyahu is trying to rally rightists by casting his center-left challengers as tools of a global campaign to usurp power.
Over social media and broadcast interviews, the three-term leader has accused unspecified foreign governments and tycoons of funneling "tens of millions of dollars" to opposition activists working to undermine his Likud party and boost the Zionist Union joint list led by Isaac Herzog and Tzipi Livni.
They, in turn, have dismissed the rhetorical fusillade as a bid by Netanyahu to shift voters' attention from socio-economic problems to security challenges such as the Palestinian statehood drive and Iran's nuclear diplomacy, on which the prime minister argues that he alone can resist pressure from abroad.
"There is a huge international effort, with major money, that is partnering up with leftist organizations here and also with media figures in order to bring down the Likud government that I head," Netanyahu told Channel 2 television on Saturday.
Speaking from his formal residence, Netanyahu said the forces he saw arrayed against him "know one thing - that when Bougie (Herzog) and Tzipi come in here, they won't stand firm even for a minute. They will fold on every position right away."
"Whether legal or not, it certainly is not legitimate for foreign governments and all kinds of donors to meddle here."
He did not elaborate, but in remarks this week Netanyahu has spoken of unspecified European governments encouraging his ousting. Another Likud minister, Yuval Steinitz, said there was American involvement, too.
Herzog, who was also interviewed by Channel 2, shot back at Netanyahu: "The international community knows you are weak."
At a speech earlier, Herzog accused Likud and Netanyahu of responding with "spin" to a public "fed up" with them.
The latest opinion polls predict the Zionist Union taking between 24 and 26 of parliament's 120 seats in the election, compared with 20-22 seats for Likud. That could give Netanyahu's challengers the chance to build the next coalition government.
He could scrape into a fourth term, however, if the Zionist Union fails to muster enough support in an Israeli political spectrum where right-leaning parties are predominant.
For now, Netanyahu says, Likud's ideological allies in parliament are a threat as they sap votes from the ruling party.
"The right wing is splitting," he told Israel's Voice of the South radio on Friday. "The right wing must unite behind me and vote Likud."
That message is unlikely to be well-received among other nationalist leaders with whom Netanyahu is expected to speak at a demonstration on Sunday in Tel Aviv's main Rabin square, where tens of thousands of opposition voters rallied last week.
Naftali Bennett of the far-right Jewish Home party, a partner in Netanyahu's outgoing government, has balked at ceding votes to Likud, saying he fears the prime minister could end up joining a broad, mainstream coalition with the Zionist Union.
Rancor has also seeped into Likud, where some officials privately blame Netanyahu for a scattergun campaign and blowback from his March 3 speech to the U.S. Congress against the Obama administration's Iran strategy.
"We're closing ranks now, but if Tuesday turns out badly for us, there will be a reckoning," one senior Likud delegate said, hinting Netanyahu could be ousted as party head. (Editing by Alison Williams)