It is time–past time–for John Kerry to tell Americans what he is about. This is less about biography (although the only information too many Americans have about Kerry comes from the $50 million negative-ad assault the President’s campaign unleashed on him) than about mission and values. He must tell voters what things–big things–he is prepared to fight for and why. It is time to start filling in the blanks, particularly on bread-and-butter issues.

Despite his recent uptick in the polls, Bush is in serious trouble and knows it. Most voters sensibly think the country is on the wrong track and prefer Democrats over the President on a range of kitchen-table concerns: jobs, healthcare, education, retirement security. They worry about budget deficits, the loss of good jobs and inadequate wages. Even after the President’s record ad barrage, fewer than half of Americans say they’ll vote to rehire him. No wonder the President thinks he’s better off spooking people about Kerry than trying to sell them on himself.

The challenge facing Kerry is how to respond to a relentless stream of attacks from GOP hit squads. This is what Bush is good at. He isn’t particularly curious about the world, doesn’t care much about policy and is AWOL when it comes to running the government. His passion, as a protégé of the late Lee Atwater, hired gun of Jesse Helms, is gutter politics.

Thus far, Kerry has been intent on proving that he’ll fight back, answering Bush’s assassins shot for shot. But that puts Kerry constantly on the defensive. Worse, it doesn’t tell voters what he is for. His first economic initiatives were similarly defensive, designed to produce headlines saying that he supports corporate tax cuts and lower deficits–no tax-and-spend liberal he. But this hardly engages public passions. The only stark contrast is between Kerry’s social liberalism–choice, the environment, civil liberties, human rights–and Bush’s right-wing social agenda.

This is not a recipe for success. It offers little to hard-pressed working families struggling with insecure jobs and wages that aren’t keeping up, while college and healthcare costs soar. If Kerry doesn’t champion their concerns, they may see no reason to get rid of a President who seems like a regular guy.

That’s why it is vital for Kerry to lay out two or three big things he’s prepared to fight for–big ideas about where he wants to take the country. These should demonstrate that Kerry understands what’s happening to working families, and that he’s prepared to fight for them. And they should stand in stark contrast to Bush’s smarmy cronyism, which serves only the few. Examples abound:

§ Rouse the nation to a new commitment to education from preschool to college, scoring Bush for breaking his promise on No Child Left Behind and doing nothing to address the real challenges our schools face.

§ Take on soaring healthcare costs. Kerry might start by calling for a new prescription drug bill mandating that the government negotiate a better price for seniors, as opposed to the shameless Bush drug-company payoff. Kerry would be wise to lay out a larger plan for healthcare, arguing that affordable healthcare for all is a matter of better organization, not more money. We already spend more than any nation in the world on healthcare as a percentage of our economy.

§ Roll back Bush’s top-end tax cuts, which are producing more jobs in China than in America, and use the money to invest here at home. Start with a crash program to move America toward energy independence. This is a jobs agenda, and a sound energy policy, in clear contrast to Bush’s Big Oil giveaway. It insures that our prosperity is not dependent on the fate of desert emirates and dictatorships. And it enables America to capture the green markets of the future while leading the world to address the challenge of catastrophic climate change, which even Pentagon planners describe as a growing danger. But whatever the ideas, it is far more vital that Kerry make himself the champion of working Americans than the guardian of fiscal probity.

Bush’s extremism will rouse the Democratic base no matter what. But this election is likely to turn on whether Kerry can convince working families that he understands and will fight for them, even as Republicans try to paint him as out of touch. If they think he’s on their side, they’ll be more ready to fire the President who has gotten us into the mess we’re in.