PHILADELPHIA (AP) _ Confident but anxious. Calm but excited. Friends described George W. Bush's conflicting emotions Thursday as he prepared for perhaps the most important address of his political career.

Bush got in a morning workout on an exercise bike and made time to attend a midday tribute to his wife Laura in the leadup to his evening speech before the Republican National Convention accepting the GOP presidential nomination.

``I saw a sense of calmness ... very relaxed and excited about tonight,'' said campaign chairman Don Evans, a longtime friend. ``He's anxious and he's ready but calm and confident.''

Seizing his moment to shine, Bush aims to deliver a 3,900-word blueprint for Americans to take advantage of the prosperity of the Clinton years and solve the unfinished business of schooling, taxes and Social Security.

In doing so, aides hope the GOP presidential nominee's acceptance address Thursday night will place some traditionally Democratic issues atop his agenda and lure swing voters into a coalition that will send a second Bush to the White House.

``I'm going to lift the spirit of the country,'' Bush promised.

The new bearer of a three-generation political dynasty, Bush has spent the early days in the shadows of a jubilant Republican convention that has tried to showcase diversity and offer glimpses of Bush's folksy style.

But Thursday night, he will take center stage and try to convince Americans his vision of the future is superior to the choice of extending Bill Clinton's legacy for four more years in the person of Al Gore.

Contrasting the divisiveness of the last eight years, Bush will try to portray himself as ``a unique leader who can ... work with both parties to tackle'' tough issues, spokeswoman Karen Hughes said.

He plans to identify five priorities _ preserving Social Security, expanding Medicare coverage for prescription drugs, improving education, overhauling the tax system and building up the military.

``We have a unique moment because with our prosperity and relative peace we have the means to tackle the tough problems before they create a crisis for our children,'' Hughes said.

Bush will deliver his speech under the watchful gaze of his father, a war hero and the last Republican to occupy the White House, and brother Jeb who is Florida's governor. His wife, Laura, and mother, Barbara, also will witness the moment.

The address will cast 2000 as a generational changing of the guard, the first election since World War II without a candidate who came of age during that era.

``Now it's our turn to step up and lead and use the wisdom we learned,'' Hughes said, sounding Bush's call.

Given the chance to avenge his father's loss eight years ago, Bush will acknowledge the prosperity of the Clinton years but portray them as a missed opportunity to have accomplished more for the graying baby boom generation, aides said.

``The tone will be regretful, rather than critical,'' Hughes promised.

Bush, 54, was elected Texas governor in 1994 after an Ivy League childhood that sent him to Andover, Yale and Harvard. The affable son of a former president and a wealthy Northeastern family, Bush struck it rich in his own right in 1989 when he became managing partner of the Texas Rangers.

With wife Laura, a former librarian, Bush has twin daughters, Jenna and Barbara.

Bush's sister, Doro, says she never would have guessed any of her brothers would follow in her father's footsteps and run for president. But with a $90 million warchest, the younger George Bush defeated formidable GOP challengers this year to emerge as the party's nominee.

His acceptance address has been finished for a week and Bush has practiced it several times, at a friend's house in Cincinnati and at Pennsylvania Gov. Tom Ridge's mansion in Harrisburg. Aides estimate he will take at least 38 minutes to deliver it, including applause.

By comparison, Bob Dole and Bush's father each took 57 minutes at the 1996 and 1992 conventions. Bill Clinton took 66 and 52 minutes accepting his nominations in those years.

Before taking the stage, a ``very personal'' film about his life and values will fill the convention center, said media adviser Stuart Stevens. Titled ``The Sky's the Limit,'' the 9 1/2 minute film will include interviews with Bush and his wife, and views of their Crawford, Texas, ranch.