With this year's Virginia political season coming to a boil, Prince William County Supervisor John D. Jenkins has the kind of problem any politician would envy.

Jenkins, a Democrat who represents the Neabsco District in the eastern section of the county, is one of Prince William's most formidable vote-winners and he has raised more than $10,500 to preserve his seat. But with no opposition in either the June primary or the Nov. 3 general election, spending that money has required imagination.

So far this year, according to disclosure forms, the Jenkins for Supervisor Committee has spent $164 to list the candidate in Who's Who in the East, $144.90 for a listing in Who's Who in the World, and $25 to enter a constituent in a beauty pageant.

Under Virginia state law Jenkins' expenditures are perfectly legitimate. Candidates must document their expenses, but they can spend campaign money for anything.

"A candidate can take a trip to Europe as long as he's willing to put it down on a form," said Susan Fitz-Hugh, secretary of the State Board of Elections.

A candidate might need special confidence in his supporters' good will to buy fur coats or vacations with his campaign funds. But the practice of candidates with no opposition to raise large bankrolls is entirely routine, according to the state-mandated disclosure documents.

Unopposed candidates raise money in hopes of persuading potential rivals to stay out of the race, to make contributions to other politicians with greater need for the money, and to pay for newsletters and other constituent services, according to local and state officeholders. Moreover, these officials said, many unopposed candidates nurture ambitions for higher office and hope to use their unspent funds in future campaigns.

Virginia has no limits on how a candidate can spend campaign funds, or what to do with unspent funds at the end of a campaign.

In Maryland and the District of Columbia, laws require that campaign funds be spent for political purposes, but as a practical matter such restrictions have proved difficult to interpret or enforce, according to government officials and representatives of watchdog groups such as Common Cause.

Most unopposed candidates interviewed for this article were frank about their fund raising and expenditures.

Jenkins, for example, said the Who's Who listings were just another part of what is an unending effort for any successful politician -- staying in the public eye.

"Being selected for a book that gives you exposure gives you credibility," said Jenkins. "What you need to be able to do is sell yourself as a candidate."

Jenkins likened the Who's Who entries to buying space in high school football programs, a common political practice in Prince William. Sponsoring a beauty pageant contributes to "good will" in the community, Jenkins said.

When he raised most of his money this spring, Jenkins said, he did not know whether he would be facing a candidate in the general election.

"You wage your campaign from the day you take office," said Jenkins, whose populist style and high visibility around his Dale City community have led many political observers to conclude that he is unbeatable. "When you're in public office, you're always running -- if you want to stay in office."

State Sen. Wiley F. Mitchell Jr. (R-Alexandria) agreed. "The surest way to be defeated in the next election is to rest on your laurels and do nothing in the current election," declared Mitchell, who said he has raised about $40,000 this year despite having no opposition.

Mitchell said he will spend about $7,000 to $12,000 on mailings and advertising related directly to this year's campaign and will spend $10,000 to $15,000 more to buy a computer system that will allow him to maintain voter lists, constituent information and other data helpful to running a political operation. He said he will likely roll the remainder into a future campaign fund.

Mitchell has been mentioned in Richmond as a possible candidate for the Republican gubernatorial nomination in 1989. Mitchell said he will give no consideration to that issue until after the current election.

His unopposed status has almost become the norm among members of the Virginia General Assembly. This year there are contested seats in only 38 of 100 House of Delegates races, according to the state branch of Common Cause. Of 40 Senate seats, 23 are being contested.

Although local and state candidates in Virginia could legally transfer funds from one campaign to another, a politician could face a roadblock by seeking to carry over unspent state funds to a federal election, such as a race for Congress.

Unlike Virginia, the Federal Election Commission does not allow individual donations of more than $1,000 or corporate or union contributions that are not given by a registered political action committee, spokeswoman Sharon Sndyer said.

Although state laws give broad latitude to candidates to raise and spend money, many political observers say the prospect of public contempt serves as a check to possible abuse.

In Prince George's County, for example, County Council member James M. Herl drew unfavorable publicity and raised eyebrows from other politicans last year when he charged to his campaign nearly two years' worth of lease payments on his car.

Herl, who handily beat his opponent in a Democratic primary and was unopposed in the general election, said they were a legitimate campaign expense. State officials said the expenditures were unusual, but not prohibited.