John F. Kerry released his closing television appeal yesterday, adding stem cell research to his short list of priorities, as President Bush launched one last attack ad against his Democratic challenger.

Meanwhile, the Bush campaign acknowledged using computer editing to produce a better shot of a military crowd shown in what was to be the president's closing ad Wednesday. The admission came after the liberal blog Daily Kos reported that some faces in the crowd appeared several times.

Kerry adviser Joe Lockhart called for the ad to be pulled, saying: "Now we know why this ad is named 'Whatever It Takes.' This administration has always had a problem telling the truth from Iraq to jobs to health care."

A day after that 60-second ad reprised his GOP convention speech about the difficulty of ordering Americans into battle, Bush returned to the negative road with a spot that ends: "Apparently there really is nothing John Kerry won't say." Bush aides say the commercial will air in selected battleground states but receive substantially less play than the convention ad.

The Kerry spot, which uses uplifting music and ends with the senator reaching into a crowd, has him saying: "If you believe we need a fresh start in Iraq. If you believe we can create and keep jobs here in America. If you believe we need to get health care costs under control. If you believe in the promise of stem cell research." After mentioning budget deficits and dependence on Mideast oil, Kerry asks voters to join him "and together we'll change America."

Kerry has focused lately on expanding federally funded embryonic stem cell research, while Bush has put limits on the federal program.

Bush campaign spokesman Steve Schmidt defended the doctored ad, said the 2002 photo of a crowd in Fort Drum, N.Y., was electronically altered because part of it was blocked by the president's podium. He dismissed as "ridiculous" suggestions that it was wrong for the campaign to change the picture of an actual event to improve the shot, noting that "real soldiers" were involved. But Bush campaign manager Ken Mehlman later told CNN that "we're correcting the editing error" to substitute the unaltered photo.

The newest Bush spot, which recycles previous attack lines, is a bit unusual in that it is a negative assault on a positive Kerry ad. "Just when you thought there was a limit on what John Kerry would say, now he claims he'll always support our military," the narrator says. "The same Kerry who voted against 87 billion for our troops in combat in the war on terror. Against body armor, bullets and supplies. The same Kerry who after the first attack on the World Trade Center proposed slashing America's intelligence budget."

The last-minute ad makes no mention of Iraq, instead referring to the "war on terror." Kerry has said that he opposed the $87 billion funding bill for Iraq and Afghanistan as a protest against the administration's Iraq policy, after the failure of his proposal to link the measure to a rollback of Bush's tax cuts for the richest Americans. Kerry's 1994 proposal to cut $1 billion in intelligence funding was smaller than those of some GOP lawmakers, including current CIA chief Porter J. Goss.

Bush, who mounted an unprecedented negative advertising assault on Kerry in March and never really let up, is ending on a similar note. Kerry abandoned a largely positive ad campaign in September to match Bush spot for negative spot.