Sarah Sands: Toxic Bush's better half is his best advert

If you thought Sarah Brown heroic in her defence of her husband, how would you describe Laura Bush's interview with Sky's Adam Boulton on Friday night?

We have hardly heard from President Bush since he left office and so his legacy has been decided by satirists, by the contrasting rebuke that is President Obama and by events. Iraq and Afghanistan did not become precious and grateful examples of democracy in action. The Lord of the Rings world view now seems unsophisticated. The axis of evil has tilted away from us. When North Korea goes berserk, we say that it is no longer our problem, let China deal with it.

Laura Bush seemed out of date even in her prime. She reportedly disliked being viewed as a "Fifties throwback". According to Kitty Kelley, who leaves no stone unthrown, Laura was probably on anti-depressants to get her through her marriage. Kelley's witness and Laura's sister-in-law Sharon Bush portrayed Laura as a rather pathetic Tennessee Williams figure. "Laura just sat around on the porch reading and smoking cigarettes. She really didn't talk much at all. Just read paperbacks and smoked cigarettes."

The differences between Laura Bush and her successor, Michelle Obama, could not be more striking. Michelle is modern, strong, inspiring. Her expectations of herself, her husband and the world are high. "You can be anything you want," she challenges schoolchildren.

What charismatic role models sometimes lack is the humour of deprecation. I can't see Michelle turning in the performance Laura managed at the White House correspondents' dinner. Her joke about her husband's love of early nights was excellent. "I said, George, if you want to end tyranny in the world you are going to have to stay up later." Michelle's criticism of Barack's messiness round the house, copied by Sarah Brown and Samantha Cameron during the election, is a generic joke about men. Laura's humour is specific and based on reality.

Her concerned line that "many mothers these days are just not involved in their children – not a problem for Barbara Bush" was a really funny recognition of the ferocious matriarchal ambition of her mother-in-law. President Obama is dazzling and witty but George Bush was plain funny. His ignorance was sometimes real and sometimes for comic effect. For the most ideological of presidents, he took people as he found them. He was without pretence. This was why Tony Blair was drawn to him, against all the odds.

In Laura Bush's new book, Spoken from the Heart, she reveals that she believed in gay marriage and abortion, two great Republican sins. It mattered not a jot to her marriage.

Reviews of the book complain that it is short on electrifying revelations, but that is partly the Bush style. Laura dismisses her husband's former alcoholism as "a bore". This shows a librarian's ability to find exactly the right word. The Bushes are from a different generation and different world, but we should not entirely dismiss it. I miss some of the old-world courtesy and Texan good sense. Their visceral connection to the British, through shared experience of the Second World War, and their genuine delight in the Queen is in contrast to President Obama's cooler appraisal of Britain. "How much more love do they want?" he asked an adviser impatiently.

George Bush's reputation is currently toxic, and the outbursts from Dick Cheney have not helped, but history may be more forgiving. Laura Bush's book is partly about testing the waters to see if it is safe for her husband to come out of his self-enforced purdah. She is as good a character witness as he could wish for.