For Barack Obama, all roads to the White House lead through Florida – and Israel

When Barack Obama spoke at a rally near Cape Canaveral two days ago to press home his support for the local space industry, a single heckler persistently shouted from the back of the crowd, "What about Israel?". It was a reminder – as if he needed it – that his hold on the crucial Jewish vote in South Florida may be in jeopardy.

For weeks now, the Mitt Romney campaign has been touting the notion that when it comes to Israel, the United States has not been the friend it is meant to be under President Obama. And it is being brazenly trumpeted up and down the interstate highways in this part of Florida with billboards proclaiming, "Obama… Oy Vey!"

In 2008 Mr Obama won the votes of 78 per cent of Jewish Americans; Mr Romney making inroads into that support could have important consequences, particularly in swing states with small, if significant, Jewish blocks like Ohio, Pennsylvania and especially Florida, where the margin of victory for either side might be very slim indeed. George W Bush took Florida in 2000 from Al Gore, with the help of the US Supreme Court, by 537 votes. Last night Bill Clinton was due in Miami to address grassroots supporters.

The sudden focus on the Jewish vote is a reminder that Mr Obama is in essence fighting multiple campaigns at once. There is the national platform with its overarching theme of defending the middle class, and beyond it there are sub-campaigns tailored to a wide range of key individual constituencies, including women, retirees, gays, African Americans, Hispanic Americans, Jewish Americans, veterans (and, yes, even space industry employees). Appealing to those groups – each was assiduously wooed from the stage at the Democratic convention - is especially important in an election which hangs on a sliver of undecided voters in only seven or eight states.

Not everyone agrees that Mr Obama is guilty of forsaking Israel. Professor Robert Freedman, of Baltimore Hebrew University, points to increased military aid for Israel and the lengths the US went to last year to block efforts by the Palestinian Authority to use the United Nations as a forum to achieve statehood. "Mr Obama has been the best US president for Israel in history," he wrote in the Baltimore Sun.

However, it is an impression that the Republicans have nurtured, pointing to slow progress on Middle East peace and to Mr Obama's reluctance to support an Israeli strike against Iran. They also highlight the difficult relationship between the President and Israeli Prime Minister Benjamin Netanyahu.

"The only thing they can try to talk about is to scare Jews on Israel," commented Marc Stanley, chairman of the National Democratic Jewish Council. "Because if they go to the other issues Jews care about – choice, education, poverty, health care, social justice, civil rights, equal rights – Jews resoundingly vote Democratic."

Random conversations with Jewish voters suggest he may be right. "Obama has done everything he could possibly have done [to support Israel and tackle Iran]," said Dan Goldstein, 67. "It's very easy for the Republicans to say anything negative about the Democrats."

"The Republicans are very adept at inventing a story that suits their goal of stripping Mr Obama of his accomplishments," says Morty Esam, 76, who is more concerned with the economy and what he says has been Republican obstructionism. "The Republicans are committed to blocking anything that Obama might accomplish in Congress and they use that as fodder to say the Democrats haven't done enough."

The Democrats did not help themselves at the convention when they first failed to state in the party platform that "Jerusalem is and will remain the capital of Israel". It was reinserted with a floor vote at the request of President Obama. That he felt the need to intervene was itself revealing: he knows that losing even a single Jewish vote is something he cannot afford.