Presidential candidates traditionally close their advertising campaigns on a positive note. But not this year.

In new ads released yesterday and targeted at the tightest battleground states, President Bush and John F. Kerry made some effort to sell their policies but did not abandon the negativity that has marked their airwaves battle for the past two months.

The president's ad begins on an uplifting note, saying Bush and his congressional allies -- no mention of Republicans -- want "strong leadership to protect America, tax relief, common-sense health care and [to] strengthen and protect Social Security." But the spot then charges that Kerry and his "liberal allies" are for "higher taxes, voting to tax Social Security benefits, government-run health care, a record of slashing intelligence and reckless defense cuts."

The tag line: "Alone in the booth -- why take the risk?"

Despite Bush's repeated charge, Kerry has not proposed a "government-run" health plan. Analysts say the ad, like Kerry's, appears designed more to motivate core supporters than to persuade undecided voters.

One of three Kerry ads unveiled yesterday is positive, with the senator from Massachusetts telling middle-class voters, "You need someone to fight for you." The second is mostly positive until Kerry says: "The president is satisfied with an economy of lower-paying jobs. I'm not."

In the unusually defensive third spot, he chides the president for insisting that Kerry would impose a "global test" on U.S. military action, a phrase the Democrat used in one debate.

"They're misleading Americans about what I said," Kerry declares in the ad. "I will never cede America's security to any institution or to any other country. No one gets a veto over our security, no one." In an implicit criticism of the Iraq war, he adds: "I will never take my eye off Osama bin Laden, al Qaeda and the terror in Afghanistan."

Kerry spokesman Chad Clanton calls the contrast in commercials "hope versus fear, real plans versus empty promises." Bush spokesman Steve Schmidt said the GOP ad shows "the president has a dramatically different approach" to vital issues. Bush plans one final ad this week.