The annual Marine Corps Marathon was underway for just a few minutes yesterday when it became clear that something was slightly screwy this year.

"Go, Elvis!" one spectator shouted to a runner in a black-haired wig and sunglasses.

The King was trailed by a woman wearing glittery devil ears, who was followed by a man in a foam cowboy hat. Elsewhere in the crowd of ground-pounders was a blue-suited Captain America, a cape-trailing Superman and Kermit the Frog, who was already getting warm in his full-body Muppet suit -- green pants, green long-sleeve shirt and green cotton Kermit mask that covered his mouth and nose.

"My nose is already running because of the hot air inside," said Kermit, 46, a retired naval officer from Waterford, Wis., who in non-amphibious life is known as Gary Paetzke.

Such was the dedication of runners who played dress-up for the marathon, which for the first time in its 29-year history fell on Halloween. Of the nearly 23,000 registered runners, about 50 men and women signed up to wear Halloween costumes, though organizers said the total number of decked-out participants was probably higher.

Dozens of others accessorized their tank-top-and-shorts outfits in honor of another U.S. ritual: Election Day.

Two days before voters head to the polls, both Democrat and Republican runners couldn't resist using one of the most famous marathons in the country as a traveling political platform.

Many runners wore Bush-Cheney or Kerry-Edwards stickers and T-shirts.

One runner wore a "Run Against Bush" T-shirt; another wrote "Kerry in a landslide" on the back of hers. A "Bush/Cheney '04" placard sailed high in the hands of a runner passing Mile 5 outside Georgetown. And soldier Rick Jansik proudly stuck a blue pro-Bush sticker above the race number across his chest.

The two rival camps were often side-by-sweaty-side, taking this year's neck-and-neck political race to new extremes. "I didn't hear anything negative," said Jansik, 43, of his Kerry-supporting running mates. "It was pretty friendly."

Wearing a bulky costume while running 26 miles, 385 yards from Arlington to downtown Washington and back takes a special breed. A determined man in firefighter gear -- helmet and heavy brown coat and pants -- could be seen rounding a corner in Crystal City near Mile 23, looking as if he were sprinting to a two-alarm.

Organizers welcomed costumes but told runners that masks were not recommended because of "personal safety and security reasons."

The Halloween gear was nevertheless an easy identifier for the thousands of spectators who lined the course and called out encouragement to Captain America, Wonder Woman and Beer Man.

"Beer Man, yeah!" one man yelled at Matthew Kim a few minutes after he crossed the finish line at the Iwo Jima Memorial in Arlington. Kim, 42, of Burke ran the course with a tall cloth beer mug on his head.

"Because I wore this," he said, "a lot of people cheered me on."

Kermit knows the feeling.

Paetzke has donned a Kermit suit for each of the 11 Marine Corps marathons he's participated in, even signing his name Kermit Frog or Kermit T. Frog on the official application, "so when you look through the results, you'll see that Kermit the Frog ran the race," he said.

Paetzke said he doesn't mind the uncomfortable, head-to-ankle suit and isn't even bothered by the less-than-flattering comments he's often received from runners near the end of the race.

"They're not real happy that a frog is passing them," Paetzke explained. "They tend to take it personally. I've had people say, 'You're not going to beat me, Kermit,' and race me to the end."

He said he wears the suit to give competitive runners a simple reminder: Have fun. Running "doesn't have to be a painful experience," he said. "There's joy to be had."

Ellen Vitro, center, of Atascocita, Tex., and Elena Fress of Pearland, Tex., went patriotic for the Marine Corps Marathon. Dozens of runners wore costumes.Lisa Foradori of Huntersville, N.C., and a pack of other runners cross the Key Bridge into the District. Nearly 23,000 people registered for the race. For the first time in its 29-year history, the marathon fell on Halloween.