The 1978 campaign for county executive in Montgomery County offers telling evidence that there is no such thing as a fiscal liberal during what is being called the year of the taxpayers' revolt.

Even here on the affluent rim of Washington, in a county where the median family income exceeds $26,000 and where one-quarter of the workforce holds virtually recession-proof employment in the federal bureaucracy, the political dialogue this year reflects a Proposition 13 mentality.

The Democratic primary finds three men - all of whom say they are Democrats because they believe it is the party on the cutting edge of social change - taking incessantly and with grave concern about fiscal restraint and cost-effectiveness and zero-based budgeting.

The Republican primary finds three men - all of whom say they are Republicans precisely because they believe their party has always represented fiscal conservatism - talking skeptically about how, in the words of one GOP candidate, "the Democrats are trying to be more Republican than the Republicans."

There is a certain irony to the Republicans' plaint, for Montgomery County has traditionally been a place for two of every three voters registered as Democrats and where, as a rule, those Republicans who mangage to win - such as former congressman Gilbert Gude and his successor, Newton Steers - do so by appearing nearly as Democratic as the Democrats on social issues.

"I'm not at all convinced that the issues, or the philosophies have actually changed," said the county's Democratic Party chairman, James Doherty. "But the specter of Proposition 13 (the initiative that sharply reduced property taxes in California) is everywhere. The Democrats simply have to somehow or other convey to the people that taxes aren't going to go up. If they don't do that, they aren't going to win."

In their attmpts to convince the voters of their fiscal responsibility, the three Democratic contenders have been stressing personal backgrounds and characteristics that are intended to distinguish one from the others.

Royce Hanson, chairman of county planning board, speaks of his executive experience at that job and how he reduced the park and planning tax rate in the county through the use of zero-based budgeting.

Charles Gilchrist, a state senator, emphasizes his experience as a tax lawyer and as a legislator who has, for four years, dealth with multimillion dollar budgets and taxation problems.

John Menke, a county councilman, points to his reputation as "one of the two most fiscally conservative" members on the council.

In separate interviews last week, the three Democrats said they felt practical government experience was the most important issue in their primary and that they did not feel at all uncomfortble campaigning in what they agree is a basically conservative climate.

If we don't overact to it, it offers a real opportunity for discipline," said Gilchrist the other day, as he sat in the living room of his grand Victorian home in Rockville, sipping a tall glass of lemonade. "It's quite possible that human problems can receive as much attention as before, but with less waste.

"And one plus in this period of fiscal restraint is that the private sector will have to face up to its own responsibilities - it will have to take on a stronger role in improving the quality of life. That's good challenge, if we can think it through right."

Gilchrist's sentiments was repeated, almost to the letter, by Hanson and Menke, which underscores another peculiar facet of the 1978 county executive campaign: the Democratic candidates appear to agree on a number of things.

The modern history of Democratic politics in Montgomery County has featured what chairman Doherty politely calls fratricide. The divisions have been deep, bitter and, above all, complex. "I'm not facetious in saying tht hatred is the grease that keeps the political wheel rolling around here," said one precinct worker. "It's really hard to understand unless you've been out here for years, and honestly, it's probably not worth trying to understand anyway."

With that thought in mind, suffice it to say that sometimes the divisiveness has been rooted in issues - such as how fast and where the county should develop - and sometimes it is merely rooted in personalities. There are times, of course, when the issues and the personalities conflict. Here is one example that may demonstrate the complexity of it all.

Hanson, in his role as planning board chairman and as the party establishment's congressional candidate in 1964 and 1966, greatly disturbed many liberals in the heavily populated Friendship Heights-Bethesda area. They said he was part of the party machine and that his planning policies reflected the desires of major developers.Some of these people are supporting or thinking about supporting Hanson this year, however, partly beacuse someone they dislike even more - former congressional candidate Lanny Davis - is supporting Gilchrist.

Hanson, Gilchrist and Menke acknowledge that some of their supporters may be motivated by old antagonisms. But unlike the county executive race in 1974, when the hostilities were out in the open, the race this year is being played out at a low-key level. In 1974 the party was bitterly split between Idamae Garrott, a maverick and William Sher, the organization candidate.

The reasons for the relatively subdued atmosphere this year have to do with the lessons of the past and the personalities of the current candidates. Hanson, Gilchrist and Menke are by nature moderate people, and each has made a concerted effort to find a middle ground.

The result has been somewhat paradoxical. Although the three say that they would rather talk about issue than personalities, their positions on issues have been markedly similar.

All three, for example, say they are glad that an 8-year sewer moratorium has been lifted in the county and that they would like to oversee a careful phase of new growth along the properly-zoned corridors leading from Washington to the outer recesses of the county. They all dismiss the "total growth versus no-growth" debates of the past as phony and out-dated.

They agree, also, on the most heated issued of the day - rent control. They are against attempts to reinstitute the control that ended last January, saying rent control is a short-term solution to the long-term housing problems the county faces and that it discourages the construction of low-and moderate-income apartments that many county residents need.

Menke has taken the most criticism from rent-control advocates, since he is the councilman who drafted and pushed the decontrol measure through the County Council.

Gilchrist's statements on rent control have been the least precise. He has said that he opposes it, but that he is also upset with the manner in which landlords have responded to voluntary rent guidelines and that if rents continue to rise he would "consider" requiring that substantial rent-increase requests, be subjected to review.

It is positions of that sort that have led some of Gilchrist's critics to call him "Good Ole Charley." Menke, who is considered the underdog in the race, claims that he has had "a helluva time" getting Gilchrist to reveal specific positions on most issues. Gilchrist, for his part, maintains that his positions are clear. He said that he has angered some Democrats, but pleased more, by "attempting to cut across some of the factions we've had before."

Hanson and Menke have attempted to do the same, and they, too, hav found some critics among their past supporters. Hanson, who was presumed to have the most support among party regulars, found himself drawing fewer votes than Gilchrist at an organization endorsement convention that ended up endorsing no one for county executive. And Menke, the candidate with the fewest party ties, upset many of the civic-activist types that his grass-roots campaign needed because of his rent control position.

A story of the Republican candidates for Montgomery County executive will appear next week.