There is plenty on the line for Prime Minister Benjamin Netanyahu on Monday when voters in Israel head to the polls for the third time in a year, but Donald Trump also has a stake in the outcome.

The US president and the Israeli leader did little last month to hide their mutual affection as they strode side-by-side into the East Room at the White House to roll out Mr Trump's long-anticipated Israeli-Palestinian peace plan. The politically adept Mr Netanyahu sent a signal to voters back home about his relationship with Mr Trump, a country on which his depends for military equipment and defence dollars.

"President Trump, Donald, I'm honoured to be here today," Mr Netanyahu said, daring to do something every other world leader avoids while standing in the White House: Calling the ego-driven American president by his first name. Even Trump himself typically refers to himself as "Trump" when speaking publicly in the third person.

Israel's coming election and the man who wants to take Mr Netanyahu's job, a former military general named Benny Gantz, came up several times. Mr Trump, for the most part, tried to remain objective. He gave both incumbent and challenger credit for endorsing his peace plan and being willing to use it to start a round of negotiations with Palestinian leaders; that offer, however, was immediately rejected.

Yet, Mr Trump let his affection for Mr Netanyahu show during several telling moments. One came when Mr Trump was touting a map included in his dead-on-arrival peace proposal that sketches out a disjointed Palestinian state spread across various sections of Israel.

Israel election 2019: Netanyahu battles to hang on to power Show all 20 1 /20 Israel election 2019: Netanyahu battles to hang on to power Israel election 2019: Netanyahu battles to hang on to power An Israeli man holding his dog casts his ballot EPA Israel election 2019: Netanyahu battles to hang on to power Chief Rabbi of the Vizhnitz (Hasidic Dynasty) Israel Hager (left), casts his ballot AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Israeli Prime Minister Benjamin Netanyahu and his wife Sara casts their votes AFP/Getty Israel election 2019: Netanyahu battles to hang on to power A man takes a selfie with his mobile phone as he casts his ballot Reuters Israel election 2019: Netanyahu battles to hang on to power An Arab Israeli woman votes during Israel's parliamentary election at a polling station in Kafr Manda near Haifa on September 17, 2019. (Photo by Ahmad GHARABLI / AFP)AHMAD GHARABLI/AFP/Getty Images AHMAD GHARABLI AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Israel's former defence minister Avigdor Lieberman and his wife Ella cast their ballots AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Israeli children accompany their father during Israel's parliamentary election at a polling station AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Blue and White party leader Benny Gantz and his wife Revital vote AP Israel election 2019: Netanyahu battles to hang on to power Israeli Prime Minister Benjamin prepares to vote AP Israel election 2019: Netanyahu battles to hang on to power A family votes in the settlement of Tekoa AP Israel election 2019: Netanyahu battles to hang on to power Ballots lies on a table AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Israel's former justice minister Ayelet greets supporters after casting her ballot AFP/Getty Israel election 2019: Netanyahu battles to hang on to power An elderly ultra-Orthodox Jewish man casts his ballot at a voting station in the city of Bnei Brak during the Israeli parliamentary election on September 17, 2019. (Photo by Menahem KAHANA / AFP)MENAHEM KAHANA/AFP/Getty Images MENAHEM KAHANA AFP/Getty Israel election 2019: Netanyahu battles to hang on to power A mother takes a photograph of her daughter near a ballot box Reuters Israel election 2019: Netanyahu battles to hang on to power Children stand with their relative as they place his vote in a ballot box Reuters Israel election 2019: Netanyahu battles to hang on to power A woman holds her dog's leash as she prepares to vote Reuters Israel election 2019: Netanyahu battles to hang on to power An ultra Orthodox Jewish man casts his ballot during Israel's parliamentary election, at a polling station in Rosh Haayin, on September 17, 2019. (Photo by Jack GUEZ / AFP)JACK GUEZ/AFP/Getty Images JACK GUEZ AFP/Getty Israel election 2019: Netanyahu battles to hang on to power An Israeli woman casts her ballot during Israel's parliamentary election at a polling station in Tel Aviv on September 17, 2019. (Photo by GIL COHEN-MAGEN / AFP)GIL COHEN-MAGEN/AFP/Getty Images GIL COHEN-MAGEN AFP/Getty Israel election 2019: Netanyahu battles to hang on to power Israel's head of the Joint List alliance Ayman Odeh casts his ballot accompanied by his family AFP/Getty Israel election 2019: Netanyahu battles to hang on to power epa07847854 Ultra-Orthodox Jews register at polling station during the Israeli legislative elections, in Jerusalem, Israel, 17 September 2019. Israelis are heading to the polls for a second general election, following the prior elections in April 2019, to elect the 120 members of the 22nd Knesset, or parliament. According to the Israel Central Bureau of Statistics, about six million people are eligible to vote. EPA/ABIR SULTAN ABIR SULTAN EPA

"This is the first time Israel has authorised the release of a conceptual map illustrating the territorial compromises it's willing to make for the cause of peace and they've gone a long way," Mr Trump said. "This is an unprecedented and highly significant development."

Then came a made-for-campaign-season remark that could give the sitting prime minister a leg up when voters cast ballots there yet again: "Mr Prime Minister, thank you for having the courage to take this bold step forward."

Former foreign policy officials and analysts noticed the map moment -- and Mr Trump's preference towards Mr Netanyahu.

"The plan's announcement was never about starting negotiations between Israelis and Palestinians, let alone reaching an agreement. From its inception the Trump administration's intensely pro-Israel peace team sought to abandon the approach of the previous three U.S. administrations and reframe Washington's policy towards a two-state solution so that it closely aligned with Netanyahu's vision of Israel's borders," according to Aaron David Miller, a former senior US official who has advised Republican and Democratic secretaries of state.

"Trump inherited a nearly dead two-state solution. He may well end up burying it on his watch," contends Mr Miller.

Why? One reason: To keep a trusted and loyal ally in power in a key Middle Eastern capital.

"The Trump administration deems it useful if possible to keep Netanyahu around through the US elections to help shore up its pro-Israel base," according to Mr Miller, calling the peace proposal "preternaturally oriented toward" the sitting Israeli PM.

Though Mr Trump is underwater, according to multiple polls, with Jewish-Americans, Israel matters to his conservative base.

A lot.

That support has swelled over the past two decades, according to Gallup, an independent polling agency.

Just over half, 59 per cent, of American Republicans supported Mr Netanyahu's country in 2001. Fast forward to a Gallup survey taken last year: That figure had jumped to 76 per cent.

There has been a surge in support for Israel among Republicans over the past several decades, according to an annual survey by Gallup. In 2001, 59 per cent of Republicans and 42 per cent of Democrats sided with Israel in the conflict with the Palestinians. As of last year, however, that figure is dramatically higher for Republicans at 76 per cent, and only slightly more for Democrats at 43 percent. And Gallup have found last year that 65 per cent of Republicans support Mr Netanyahu, making him a a key to Mr Trump's efforts to hold together is voting coalition in the six or seven swing states that will matter most come November.

Democratic lawmakers also see Mr Trump and Mr Netanyahu as politically linked, both with plenty to lose come Monday.

So close does House Foreign Affairs Committee member Ami Bera, a California Democrat, see the two leaders that he called the peace proposal a "plan that the president put out with Prime Minister Netanyahu."