Among the many mysteries to which a bleary-eyed America awoke the morning after the inconclusive 2000 presidential election were the results from Florida's Palm Beach county. Heavily Jewish and overwhelmingly liberal, its voters appeared to have cast 3,407 votes - more than three times his vote in any other county in the state - for Pat Buchanan, an ultraconservative candidate who had faced multiple accusations of antisemitism.
In truth, there was little mystery as to what had occurred in Palm Beach: a badly designed ballot paper had confused many elderly Jewish residents, leading them to vote inadvertently for Mr Buchanan. The consequence of their understandable bewilderment had historic ramifications: it deprived the Democrat presidential candidate, Al Gore, of the couple of hundred votes he needed to carry ultra-marginal Florida and, with it, win the presidency.
Polls carried out since the FBI announced last Friday that it was re-opening its investigation into Hillary Clinton's emails suggest the 2016 race could turn into a nail-biter. If so, Mrs Clinton will have good grounds for hoping that, in those swing states where she needs their backing, Jewish voters across the country will be rather more helpful to her cause than those of Palm Beach were to Mr Gore's.
Polling and history suggest they will be. Jews have long been steadfastly Democratic. Not since Warren Harding in 1920 has a Republican presidential candidate managed to win a plurality of the "kosher vote" - and this was only thanks to one in three Jews abandoning the Democrats to vote for the Socialist third-party candidate Eugene Debs. Jewish support for the Democrats has occasionally risen as high as 90 per cent, hitting that level for Franklin Roosevelt in 1940 and 1944 and Lyndon Johnson in 1964.
More usually, the party has been able to rely on a slightly more modest, but still overwhelming, 70-80 per cent of the Jewish vote. In the post-war era, Republicans such as Richard Nixon in 1972, Ronald Reagan in 1980 and George HW Bush in 1988 only managed to win the votes of slightly more than one-third of Jews even as they were clocking-up crushing electoral victories. Thus, since 1928, just one Democrat - Jimmy Carter in 1980 - has won the votes of fewer than six in 10 Jews, while Dwight Eisenhower in 1956 is the sole Republican since Mr Harding to win the votes of more than 40 per cent.
When America last elected a president four years ago, support for Barack Obama among Jewish voters dipped from the 78 per cent he secured in 2008 to 69 per cent, allowing his Republican rival, Mitt Romney, to win the support of 30 per cent of Jews - the party's highest total in 24 years.
However, Democrats will hope this was simply a blip, caused, in part, by the president's rocky first-term relations with Israel. As Dr Ira Sheskin of the Sue and Leonard Miller Centre for Contemporary Judaic Studies at the University of Miami, suggested to the Jewish News Service earlier this year, the long-term trend casts doubt on the hopes of conservative analysts that Jewish voters might yet find a home in the Republican party. Between 1972 and 1988, the Republicans won on average 32 per cent of the Jewish vote. Since 1992, that figure has dropped to 22 per cent.
A poll by the American Jewish Committee in August appeared to suggest mixed news for both of this year's candidates. It indicated that Mrs Clinton will beat Donald Trump by a three-to-one ratio among Jewish voters, even if, at 61 per cent, her support seems to be lower than that secured by Democrat presidential standard-bearers over the past three decades. However, her relatively weak showing, and the fact that Mr Trump polled the support of fewer than one in five Jews (significantly down on Mr Romney's vote four years ago) probably stemmed from the high level of support for Libertarian candidate Gary Johnson and the Green party nominee, Jill Stein. Nationally, though, both have slipped in the polls as the election approaches, suggesting that Jewish backing for the Democrat candidate, and perhaps her rival, will have risen since the summer. Moreover, a similar AJC survey in 2008 significantly underestimated the eventual level of Jewish support won by Mr Obama.
Still, Mrs Clinton is taking no chances. In the campaign's final two weeks, her husband, Bill, and former Senator Joe Lieberman, who became the first Jew on a major-party ticket when Mr Gore tapped him as his running mate in 2000, campaigned for her before Jewish audiences in Florida.
Jews are small numerically - they constitute roughly two per cent of the US adult population - but academics Daniel Palmer and David Manchester of Brandeis University's Steinhardt Social Research Institute label them a "potentially pivotal demographic" in next Tuesday's election. Jews are not only more reliable voters - at 80-85 per cent, their turnout is some 20 points higher than average - but they are also concentrated in the "battleground" states in which the election will be decided.
According to the Steinhardt Social Research Institute, the Democrats start with a heavy advantage: 54 per cent identify with the party (as against 36 per cent of all voters) and only 14 percent with the Republicans (with whom 25 per cent of voters overall identify). But with one-third of Jews identifying with neither party, there remain a sizeable minority whose votes are potentially up for grabs.
It is these so-called "independent" voters who are especially apparent in the "swing counties" of battleground states. In Florida, where the polls between Mrs Clinton and Mr Trump are neck-and-neck, Jews constitute 15 per cent of the adult population in Palm Beach county. But while 54 per cent of them identify as Democrats, 31 per cent are not affiliated to either of the two major parties.
Similarly, in Ohio, another state where polls predict a photo-finish, Hamilton county is home to more than 25,000 Jewish voters. Again, many more Jews in the county, which contains Cincinnati, identify as Democrats than Republicans, but a sizeable 9,000 voters still identify with neither party.
While Mrs Clinton has a little more room to breathe in Pennsylvania, losing the state, which Mr Trump has heavily targeted, would probably destroy her hopes of making it to the White House. All eyes in the state are on Bucks county, just north of Philadelphia, where Jews make up six per cent of eligible voters. One-quarter of them are registered as neither Democrat nor Republican and 41 per cent claim to be politically moderate - a voting bloc which tends to go with the winning candidate in presidential elections.
But, for all the talk of swing voters, the American right continues to attempt to unravel the seeming riddle of why, as Milton Himmelfarb put it in the aftermath of Mr Nixon's landslide re-election in 1972, most Jews "earn like Episcopalians and vote like Puerto Ricans". Much head-scratching has, for instance, resulted from the fact that, even as they have attempted to paint themselves as better friends of Israel than the Democrats, the Republicans have attained little uptick in support from Jewish voters.
Perhaps, however, the riddle is not so difficult to solve. US Jews are twice as likely to have liberal political views than conservative ones. By contrast, US voters as a whole lean much more to the right: nearly 40 per cent claim to have conservative views, as against 24 per cent who hold liberal ones. Thirty-six percent of Jews - almost exactly in line with voters more widely - consider themselves moderates.
Over the past two decades, however, the Republican party has hurtled increasingly to the right. Indeed, the very factor - the strangle-hold over the presidential nomination process exercised by Evangelical Christians - which has led the party to adopt an almost totally uncritical approach towards Israel (or, more accurately, the policies of the Israeli right), is also the one which has led it to endorse increasingly hardline positions on social issues.
The "litmus tests" imposed by the "religious right" on Republican candidates - opposition to gay marriage and abortion, for instance - alienate potential Jewish voters, who overwhelmingly support both. With his xenophobia and wholesale surrender to social conservatives - which produced a Republican party platform labelled the "most extreme" in its recent history by the New York Times - Mr Trump has built a campaign almost calculated to frighten off the vast majority of Jewish voters.
Even many Orthodox Jews, who polls indicate are more sympathetic to the Republicans than their fellow Jews, appear to have baulked at the prospect of President Trump. The AJC's August poll suggested only about 50 per cent of Orthodox Jews intended to vote Republican this year, down from 70 per cent who backed John McCain in 2008.
This bent towards moderation helps explain why Jews have tended to reject the populist insurgencies which have attempted to storm the establishment citadels of both US political parties over the past year. As they did in 2008, Jewish Democrats remained loyal to Mrs Clinton in the primaries, rejecting her left-wing challenger, Senator Bernie Sanders.
On the right, Jewish Republicans have been notable in their opposition to Mr Trump. Some, such as Brookings Institute fellow Robert Kagan, the neoconservative writer Joshua Muravchik and Mr McCain's former foreign policy adviser, Max Boot, have jumped ship and announced they will vote for Mrs Clinton.
Others, such as Weekly Standard editor Bill Kristol and Elliott Abrams, George W Bush's deputy national security adviser, will back neither the Republican candidate nor his Democrat opponent. "This marks an exodus of support that has not been seen since Senator Barry Goldwater's 1964 Republican presidential campaign that ended in a landslide for President Lyndon B. Johnson," commented Washington Jewish Week. And that, of course, was also the year when barely one in 10 Jews cast their votes for the Republican presidential candidate.
