The American presidential convention, be it in Denver, Chicago or Minneapolis-St Paul, is a lot like the circus.
The main thing is to see the animals in the ring, dancing, trotting and performing.
At the Democratic National Convention last week, Senator Edward Kennedy, the liberal white-maned lion, moved thousands to near-tears by showing he still had the strength to roar after a rough summer of brain cancer treatment.
The year 2008 is bringing a new act to the circus, or taking one that used to be a minor sideshow and turning it into a high-stakes piece of political performance art.
Michelle Obama and Cindy McCain, wives of the two presidential contenders, are very different women with this in common: both have had to prepare to face a new level of intense scrutiny in their convention speeches.
Michelle Obama's speech received glowing reviews and Cindy McCain is set to deliver hers on Wednesday or Thursday at the Republican National Convention.
Going in, Mrs Obama and Mrs McCain knew, in the American turn of phrase, they must "step up to the plate", and frame their husband in a kind of dewy, domestic light.
They are being sized up by voters, viewers and the political establishment - not just for the words they speak at the podium, but the colour they wear and, of course, their hair.
If they can project a bit of pathos and handle the autocue smoothly, so much the better. It is not enough to smile and wave any more.
The American presidential wife is now expected to have a poised political persona of her own.
Whether her husband is a Democrat or Republican, the spouse has to entertain the electorate for a good - or a bad - 15 minutes. (Laura Bush made her husband promise she would never have to give a speech when she agreed to marry him, but even the enigmatic first lady has given in on this point.)
It has not always been so. Ever since the outspoken Hillary Clinton morphed from being a very political first lady, during the eight years of her husband's presidency, to becoming a political candidate in her own right - running for the US Senate in 2000 - this wave has been heading to shore.
Elizabeth Dole, wife of the former Senate majority leader who lost his presidential bid in 1996, Robert Dole, spoke flawlessly on her husband's behalf at the presidential convention in an informal talk-show host style. Like Mrs Clinton, she is a senator today.
Cindy McCain has no such political aspirations.
Extremely devoted to her husband, she swims in the old school of quiet political wife. Yet she will be subject to the new expectations of a "stemwinder".
Unlike Michelle Obama, she doesn't have to win over half the house for her man. But Mrs McCain will have to deal with what has become a campaign issue - the couple's wealth and the number of houses they own - in some fashion.
Humorous self-deprecation is always effective. She will most likely emphasise John McCain as naval war hero, family man and great barbecue chef all rolled up into one.
If she's good at the job, she will translate some of her husband's manic charm.
Mrs McCain, like her Democratic counterpart, will succeed if she "humanises" her husband for voters. Americans tend to vote for the man they like better - a sad truth.
Michelle Obama's speech was fascinating for what she didn't say as well as for what she did. In one of the most carefully packaged presentations of a candidate's wife ever, she looked striking in green and spoke of herself only as a sister, daughter, mother and wife.
These are demure descriptions of a woman who made it from growing up on the South Side of Chicago to Princeton University and on to Harvard Law School.
Her impressive professional and intellectual accomplishments went for naught that opening night.
Earlier on the trail, Michelle Obama was more unbridled; she remarked that for the first time in her adult life, she was proud of her country.
That spark of spirit brought down a hard rain of criticism - and she has not been the same since.
Her speech's main anecdote was very Everywoman - about taking their first baby girl home from the hospital.
She also sought to assure people that her husband's Kansas background was every bit as down-home American as that of her Midwestern family, despite his "funny name" (Barack Obama's own words).
She acted, in a way, as an anti-Hillary, because the Clintons have presented themselves as a partnership of equals from the get-go. Michelle Obama pressed her husband's character case in a universal way that could not be accused of being elitist or stuck-up.
Looking back to the 1950s, 1960s and 1970s, presidential wives Mamie Eisenhower, Jacqueline Kennedy and Patricia Nixon were seen but not heard on festive convention nights.
Back in the 1940s, President Harry S Truman often introduced his stoic wife Bess to audiences as "the Boss", which was as far as her public personality went.
Former First Lady Nancy Reagan, once an actress, campaigned for her husband, but her first major speech at a convention was not until 1996, when she endorsed Dole. (Ronald Reagan, president from 1981 to 1989, was by then ailing from Alzheimer's disease.)
Hillary Clinton again appears to be the agent of change - or, if you like, "game-changer".
However, the game still contains clear contradictions for political wives, as shown by Senator Joseph Biden's introduction of his wife Jill after being named Obama's running mate.
At first, he bragged to supporters that she was "drop-dead gorgeous!" Then he said she had a doctorate. Finally, the loquacious Biden added: "And that's a problem."
As H L Mencken, the sage newspaperman of Baltimore, once observed, the United States is the greatest show on earth - yes, right about now.