Early last winter, Winfield Kelly invited Ilona Hogan and her husband, Larry, to his Upper Marlboro office after having appointed her to the county library board. Kelly had been through hundreds of such ceremonies during his terms as Prince George's County executive, but this was the one he would not soon forget.

"There was something in Larry's eyes that day, in the way he handled himself," Kelly recalled. "I took one look at him and said to myself: 'Oh, boy. This is it. He's going after me.'"

It was, to say the least, a disconcerting experience for Kelly. For three years, he had been conducting polls to compare his popularity with that of politicians who might run against him in 1978. Those polls showed Kelly on top against Democratic Councilman Francis B. Francois, against former county executive William Gullett and against everyone else save one man - former Republican congressman Lawrence J. Hogan.

Kelly's instincts were sharp that cold February day. Five months later, in June, Hogan entered the race for county executive, sparking one of the toughest campaigns in county history.

The reaction Kelly had to the first hint that Hogan would be his opponent - "Oh, boy" - characterized the tone of this campaign. Although a pugnacious little Irishman whose like has been graced by luck and unending success, Kelly had a hard time shaking the impression that he was overmatched or, as one friend put it, "psyched out," by Hogan.

Kelly's political aides often referred to Hogan as a "heavyweight champ" and a "movie idol" and a "folk hero." They talked openly about a how good it made Kelly feel when, on occassion, he "stood up and held his ground." Kelly himself never denied the possibility of defeat, as so many politicans do. He sometimes speculated that being county executive might be a one-term job and spoke excitedly about getting back into the business world, where he had made a million dollars.

"I'm not at all frightened by the prospect of losing," Kelly said recently. "I can live with myself no matter what happens."

Hogan began campaign with a similar ambivalence, saying that he considered Kelly a good friend and that he was not sure he really wanted to work full time as a county executive. But soon he was reestablishing his reputation as a gut-punching campaigner and jabbing at Kelly's side.

Kelly thought that Hogan had intimidated Hervey Machen, Royal Hart and Edward Conroy in congressional races between 1966 and 1972. He was determined not to let Hogan do that to him. Every time Hogan called him a liar - or had one of his aides slip a negative Kelly story of the newspapers - the county executive attempted to respond in kind.

What resulted was a vitriolic campaign in which fleetness of foot and swiftness of mouth became more important - or more evident, at least - than articulation of the county's problems and solutions to them. The candidates would trade accusations daily, then stand back and tell the voters that the opponent could not be trusted.

Although Kelly made one embarrassing slip during the give-and-take - talking on television about meetings with Hogan that took place only in Kelly's imagination - the general belief in the county by campaign's end was that neither man had gained much or lost much as a result of all this.

"After all the name-calling and promises of the last seven weeks," said one county Democrat, "this race was destined to be decided by perceptions that were years, not weeks, old."

The perceptions of Kelly - good and bad - were formed in large part by his administration's practice of what Councilman Francois dubbed "homeowner politics." Virtually every financial decision Kelly made as county executive was based on the theory that he could get reelected if he held down the property taxes of the middle-class, single-family homeowners in Bowie and Greenbelt and new Carrollton and College Park and Clinton and Hyattsville.

By last spring when Kelly finally accomplished a property tax cut for most of these homeowners, he had also antagonized other groups in the county, such as tenants, who for two years had to pay a special renters' tax. Thus, blue-collar and poor tenants, who traditionally vote Democratic, turned in large numbers to Hogan this year.

The other important perception of Kelly, and one that was rarely articulated because of its sensitive nature, concerned his handling of race relations in the county. By moving strongly to integrate the country's police and fire departments, keeping quiet on the school busing controversy and firing a white policeman who shot and killed an unarmed, black shoplifting suspect, Kelly upset rank-and-file police and old-line white conservatives.

Conversely, Kelly hoped these actions would compel the county's black voters, who constitute more than 20 percent of the electorate, to turn to him in record numbers.

The perceptions of Hogan are even older, going back to the six years between 1968 and 1974 when he served as the county's congressman, a position, unlike county executive, where it is easy to make friends and avoid making enemies. Hogan was perceived than as a tough, articulate spokesman for his blue-collar constitutency - fighting with equal vigor the "liberals" who pushed court-ordered busing and the Old Guard Democrats who were ensnarled in zoning and development scandals.