US:"The personal is political" was the battle cry of women's rights campaigners in the 1960s, but in the 2008 race for the White House, the political has never been more personal.
It's not just that all the candidates like to emphasise their commitment to key policies by declaring, "This is personal for me", before launching into a moving story about a sick relative or an account of their humble origins.
Personal friendships, enmities, snubs and slights have had a measurable impact on both the Republican and the Democratic races, to the benefit of John McCain and Barack Obama and at the expense of Mitt Romney and Hillary Clinton.
When Giuliani dropped out of the Republican race this week, he didn't have to think twice before endorsing his old friend McCain, with whom he has attended baseball games and against whom he has always refused to run negative ads. Giuliani's support could help McCain to win big states like New York and New Jersey next Tuesday, and the endorsement has already helped to consolidate the Arizona senator's image as a frontrunner.
McCain has also benefited, however, from Romney's personal unpopularity among other Republican candidates, notably former Arkansas governor Mike Huckabee, who faced in Iowa what he saw as a dishonest, negative campaign from Romney. At the end of each Republican debate, all the candidates would shake hands and chat with one another - all except Romney, who was usually left standing alone or reduced to chatting with the journalists who posed the questions.
Huckabee came in fourth in Florida this week, but his presence on the ballot helped to ensure that Romney lost the state to McCain. Romney suggested this week that Huckabee is only staying in the race to thwart him and although the former Arkansas governor may have other motives, he is not obviously upset by the damage he is causing to his old rival.
When Obama announced this week that he had raised $32 million since the beginning of January, he should have sent a "thank you" note to Bill Clinton, whose intemperate attacks on the resurgent candidate turned off so many voters throughout South Carolina and around the country.
A number of the former president's friends have told me that the attacks were motivated by Clinton's anger at Obama's slighting reference to his presidency, comparing the Clinton years unfavourably with the "transformative" Reagan presidency. "He just thought, 'who does this guy think he is?' And he went crazy," one former White House staffer said.
Clinton's ranting, particularly his insensitive handling of racial issues surrounding Obama's candidacy, helped to persuade Senator Edward Kennedy to endorse Obama. The Clintons knew that Kennedy was leaning towards Obama for some time and the former president called the Massachusetts senator a couple of weeks ago to ask him to stay out of the race.
According to one account of the conversation, Clinton reminded Kennedy of various favours the former president had done for the Kennedy family, before pleading with him to maintain a public neutrality.
The plea backfired, because Kennedy apparently regarded Clinton's approach as "heavy-handed" and decided not only to endorse Obama but to campaign for him in advance of Super Tuesday.
Clinton, who has generally been on his best behaviour since South Carolina, chewed through his muzzle late this week to make a sly dig at Kennedy, whom he coupled with President George Bush as one of the fathers of the unpopular No Child Left Behind education Bill.
If McCain wins the Republican nomination and Hillary Clinton is the Democratic nominee, the general election will be closely fought, but it is unlikely to be marked by deep personal animosity between the candidates. Clinton and McCain get along well and they bonded a few years ago during a trip to Estonia, when they took part in a drinking competition, matching each other shot for shot with local vodka.
The mood could be less rosy if Obama is the Democratic nominee, given McCain's tone in a letter to the Illinois senator two years ago, when Obama withdrew from bipartisan talks on ethics reform. "I would like to apologise to you for assuming that your private assurances to me regarding your desire to co-operate in our efforts to negotiate bipartisan lobbying reform legislation were sincere," McCain wrote.
"I'm embarrassed to admit that after all these years in politics I failed to interpret your previous assurances as typical rhetorical gloss routinely used in politics to make self-interested partisan posturing appear more noble. Again, sorry for the confusion, but please be assured I won't make the same mistake again." Ouch.
