LANSING, Mich. (AP) _ Republicans can't wait to get their hands on an upcoming book by the ex- wife of Democratic Gov. James Blanchard. Nervous Democrats wish they could put it on hold until after the November elections.

Paula Blanchard says both sides are overreacting. Her book covering the 1987 breakup of her 21-year marriage to Blanchard is due out in July.

Blanchard, who last year married Janet Fox, his former secretary, is favored for re-election this fall over likely GOP opponent John Engler, the state Senate majority leader.

Paula Blanchard's book - '''Til Politics Do Us Part'' - is a question mark in the campaign, but Michigan's former first lady predicts it won't affect the election.

''This book is not a kiss-and-tell book,'' she said. ''This book is not an exercise in vengefulness or anything like that. It's the story of my life as a political spouse and the choices I made and why I made the choices.''

Paula Blanchard supports her ex-husbands's re-election bid and predicts he will win ''based on his solid record of performance.''

Engler offers a different assessment.

He describes Michigan as overtaxed, sputtering economically, and in need of a new leader. He contends Blanchard masks an average record with a high- powered public relations machine.

''Just think what the right man could do,'' is the theme of his campaign.

Engler himself is divorced, and his ex-wife, Colleen, also has written a book that touches on the breakup of their marriage.

Colleen Engler, a former state legislator and onetime gubernatorial candidate who works for the Commerce Department in Washington, said she doesn't have a publisher yet.

''It hasn't even been edited yet. An editor might say, 'You don't want any of this stuff about John Engler in there,''' she said. ''My book is about running for governor in 1986 and then running for lieutenant governor.''

Blanchard's divorce made front-page news, as did his remarriage, but there has been no backlash from voters. In fact, the newlyweds got a warm welcome earlier this month on a two-day tour to announce his bid for a third four-year term.

Paula Blanchard said the governor and a number of his associates asked her to hold up her book until after the election.

''The curious thing is none of them have read it,'' she said. ''They were asking me to hold it based on speculation and assumptions.''

''I've encouraged Jim to read the book. After he does that, his concerns about it will be minimized. He will be able to see it's a book that puts a lot into perspective,'' she said. ''It goes directly from my heart to the page.''

Blanchard is unopposed in Michigan's Aug. 7 primary, while Engler is expected to easily defeat tax fighter John Lauve. A March poll found Blanchard leading Engler 51 percent to 31 percent, but the lesser-known Engler said that was to be expected early in the campaign.

Engler launched his campaign in February and immediately began airing television ads aimed at boosting his name identification.

Democrats say Engler's leadership is untested and focus on Blanchard's record in erasing a $1.7 billion debt, his efforts to diversify the state's economy, improve education, and fight crime while keeping the state budget balanced.

The governor's first TV ad, unveiled last month, touted Blanchard as tough on crime and set out his campaign theme, ''Tough. Tested. Trusted.''

The ad closed with a white guard yelling at a black inmate at Michigan's boot camp prison for non-violent young offenders, who volunteer for its military-style discipline.

The ad was aired everywhere in the state except Detroit, which is two- thirds black. Engler's campaign director, Dan Pero, denounced it as racist, and some black leaders and lawmakers agreed.

The ad later aired in Detroit. Blanchard defended it as showing a real answer to a tough problem and dismissed the whole controversy as being manufactured by Republicans.

The flap ended quickly and Michigan Democratic Party Chairman Tom Lewand said it was ''well behind us and not something to be concerned about.''

But Engler sees cracks in Blanchard's public image, and cites the boot camp ad, tight budgets ahead and 78-year-old Lt. Gov. Martha Griffiths' decision not to retire - which came as a surprise to the governor.

''The carefully constructed facade is in tatters,'' Engler said. ''This is a very isolated administration that isn't as finely tuned and well-oiled as people would believe.''