One is 68 years old, white-haired and wily. The other is six years younger, as cerebral as local politicians get. Their resumes bear the same liberal Democratic imprint and together read like a minihistory of Montgomery County civic and political life for the last 20 years.

But Del. Idamae T. Garrott, the older of the two, and Del. Lucille Maurer are fierce rivals whose stylistic differences and ambitions for a state Senate seat they expect will be vacant in 1986, are fueling one of the best political sideshows of the General Assembly here.

After hours in the offices of the Montgomery House delegation and around the precincts of the dagger-shaped 19th District, political junkies already are billing this as the local contest to watch for the next 18 months.

It has the trappings that only a Montgomery Democrat could love: Two articulate candidates, what promises to be a very expensive campaign and, best of all, the inevitable revival of grudges dating back to the late 1960s.

"It's the clash of the Titans," said Sen. Sidney Kramer, whose seat will be up for grabs as he campaigns to become county executive. Kramer is maintaining a strictly hands-off policy on what he described as "a real firefight" between his two longtime friends and political allies.

The firefight, of course, is months away, but already there are signs bearing out Kramer's prediction.

The two women now "watch each other like hawks" during sessions of the House Ways and Means Committee where they serve, said Del. Gerard F. Devlin (D-Prince George's), vice chairman of that panel.

"It's like a 15-round heavyweight match," Devlin said. "They circle each other, parrying and thrusting."

In December, at a private committee retreat in Cecil County, both women scrambled in front of their peers to take credit for legislation increasing education aid as the cost of living rises.

During public sessions, if one discourses on an issue, the other is sure to follow suit. And in the Friday morning meetings of the Montgomery delegation, Maurer and Garrott periodically recapitulate portions of their long careers.

If Kramer had any thoughts that Garrott and Maurer would hesitate to stake their political futures on the September 1986 primary, those were quickly dispelled just before the legislature opened, at a private meeting with both women in his Colesville office.

"I was really hoping one of the two of them would back out," Kramer said of his futile suggestion to Maurer and Garrott that one might stay in the House. "If both ladies get involved in a heated battle, a third person could come in and pick up the chips."

However, for others, the fear of a Republican representing the heavily Democratic district pales next to the prospect of a party in chaos next year.

Many believe that a bitter Garrott-Maurer race would have a ripple effect across the county, making it impossible for Democratic candidates to fashion their traditional electoral slates.

"It'll split the county open and hurt any chance for unity in '86," said Victor L. Crawford, a former delegate and senator whose seat in the House was filled by Maurer 16 years ago.

What makes some bystanders cringe -- and others salivate -- about the election is that the two delegates are so much alike and will be courting a relatively small number of primary voters in the 19th, a solidly middle-class district of nearly 34,000 Democrats that stretches from Washington Grove to Silver Spring.

"They have the same appeal because they're the same Montgomery County type: female, roughly the same age, liberal personality, good-government types," Crawford said.

Garrott, a District native, has strong ties to neighborhood associations, civic groups and the League of Women Voters, which she ran in the mid-1960s. She is arguably the grande dame of local Democratic circles.

She served eight years on the County Council and was on the board of the Metro transit authority and the local Council of Governments, was her party's nominee for county executive, ran for Congress and helped write many of the laws that earned Montgomery a reputation as one of the most progressive jurisdictions in the country.

Garrott was elected to the House in 1978 on a slate of candidates headed by Kramer. That year, Maurer led the district with 6,489 votes, compared to Garrott's 5,942. Four years later, Garrott won with 9,662 votes, Maurer with 8,793.

In her personal style, Garrott is the stereotypical Montgomery politician, a label that endears her at home but occasionally makes her the object of her colleagues' scorn here.

She has a deliberate, almost plodding approach to problems and is above all a planner, one who is willing to study a major issue for months and even years before making a decision on it.

Her detractors criticize Garrott for voting for social and spending measures without providing adequate funding for those programs, a charge she rejects as untrue.

Others attack her for sponsoring bills -- such as a recent measure on animal rights -- which they view as frivolous and self-serving.

Del. Patricia R. Sher, a Maurer supporter, said Garrott is one of several delegates who "pander to the press and the civic associations. Lucy maybe has a more dignified image, an air becoming to a senator."

In her long career in the House, Maurer, a New York City native, has often appeared aloof from the back-yard issues that dominate such neighborhoods as the giant Leisure World retirement community, Layhill and Wheaton, the heart of the district.

A member of the more traditional wing of the local party that has feuded with civic-oriented politicians like Garrott since 1966, Maurer made her political base in educational circles and was a member of the county Board of Education through most of the 1960s.

In the House, she has concentrated on government financing of education, winning a national reputation in that field.

Maurer also has been a frequent ally of Baltimore in that city's quest for education dollars, a position she staunchly defends but one that Garrott is expected to exploit in the coming campaign.

"Among the citizenry, she's controversial," said Montgomery County Del. Mary H. Boergers, a Garrott fan. Maurer's 1984 vote in favor of a pension bill opposed by teachers across the state, her favorable stance on the controversial Inter-County Connector highway and authorship of funding formulas that some believe hurt Montgomery schools "are three trigger issues that people will remember," Boergers added.

"It may come down to who fits the mold of what a senator should be," Boergers said. "It'll be a knock-down, drag-out fight."

Many mutual friends of Maurer and Garrott believe that this will be the last great campaign for both and, as such, the contest holds a certain poignancy.

"Each is the toughest opponent the other has ever faced," said Kramer. "In a way it's kind of sad. One of them will lose."