Trick or treaters could tell it wasn't your ordinary Halloween party. The Great Pumpkin and his friends were there with $10,000 to help keep that old hobgoblin, Ronald Reagan, out of the White House.

You knew exactly which goblin singer Mary Travers had in mind when she said; "I never felt America wasn't strong enough to withstand a little mediocrity in the White House, but we can't afford a president so right wing and so close to Nixon."

Thus thrashing the Republican candidate with a stout Democratic broomstick, 200 gathered last night at Sargent and Eunice Shriver's Foxhall Road estate.

Many of the guests were federal employes who told of feeling deprived by the Hatch Act forbidding them to take part in political campaigns. Last night's fund-raiser, however, technically benefiting the Democratic National Committee, made up for that deficiency.

This is the first thing I can do -- finally I can breathe." said Margery Tabankin, director of VISTA. "I've spent the last four years of my life revitalizing a program that now has 5,000 VISTA volunteers and 1,000 self-help projects that weren't there 4 1/2 years ago. Our budget has quintupled to nearly $40 million. My fear is that if Ronald Reagan is elected, there'll be no support at all from the executive branch."

Mary King, deputy director of ACTION, back from a campaign swing in Illinois, said that "Ronald Reagan talks about getting government off our backs, but he speaks for the privileged. Government is the only protection most Americans have."

Eunice Shriver, about to set off thrick-or-treating in the neighborhood with her son Blair, 14, said she thought Jimmy Carter would win on Tuesday. "But everybody's judgement on that is about as good as everybody else's."

When asked, she said "Obviously Teddy would have been best -- Teddy would have been a great candidate pulling people together. But that will come."

Rep. Gillis Long (D-La.) was off campaigning for Carter in Louisiana so Cathy Long, his wife, co-hosted with the Shrivers. Mary King's Christmas card list ("we scrupulously avoided using government lists," said King) provided the basis for last night's invitation list. She said most of the people had been associated with Sargent Shriver in programs such as Head Start, the Peace Corps, VISTA and Foster Grandparents.

Shriver introduced Mary Travers and Peter Yarrow as having been "in the forefront of nearly every effort for social justice for at least 20 years." t

When Travers and Yarrow started singing some of the songs that had put them in that forefront, a flood of nostalgia coupled with appreciation overwhelmed some listeners like Sally Ann Baynard.

"They were not only the awakening of us as people but also as a social conscience," said Baynard.

The tribute won her a kiss from Travers. And in a tribute of his own, to Travers and Yarrow legendary rendition of 'Puff the Magic Dragon,' Shriver dubbed the grassy knoll over looking a pond "dragon court."

Travers said it made her "highly nervous" that Reagan and Carter were neck-and-neck.

I'm going on 44 and coming up to my midlife crisis, and if Reagan gets in, believe me that'll be some crisis."