They are both young, both lawyers and both are making their first run for elective office.

Philip L. Chabot and Louis K. Rothberg, the contenders in Tuesday's Democratic primary for the 44th House of Delegates district seat in Fairfax County, concede that on the issues they also are pretty close together.

"Both come from basically the same point on the philosophical spectrum," said Democratic State Sen. Richard L. Saslaw of Fairfax, whose own district includes the 44th.

As a result, questions of experience and effectiveness have emerged as the major issues in the district, which has about 25,000 voters and extends south from the Capital Beltway at Alexandria and ranges from costly Potomac waterfront homes to Rte. 1 trailer parks.

In preparation for the primary, the two men have knocked on thousands of doors and courted voters at two dozen coffee sessions, trying to make their names and faces familiar in the 44th, now represented by Republican Del. Frank Medico.

As of June 3, Chabot had spent about $14,700, more than five times Rothberg's $2,900. The campaign has seen posters sprouting on lawns and bumper stickers on cars in the area, often called a swing district where either party can win.

Chabot said he has the support to beat Rothberg if residents will only avoid traditional primary apathy and vote. Rothberg termed the race "too close to call." His workers say about 1,500 persons voted in a 1981 primary in the area.

Both men call for more state money for schools, highways and Metro, passage of the Equal Rights Amendment and other long-standing goals of Northern Virginia Democrats.

Rothberg, energetic and still boyish-looking at 33, practices law in Alexandria. He stresses his experience as an aide to Del. Marian Van Landingham (D-Alexandria) and a former Williamsburg legislator, roles that he says familiarized him with the personalities and processes that turn ideas into law in Richmond.

As an aide, he said, he conceived of and wrote two bills that eventually were enacted, one to waive fees for some senior citizens attending state-supported schools and the other to revise rules of evidence used in court. "I've (already) got two of my ideas sitting in the Code of Virginia," he said.

"I've come as close as you can to being a delegate without being a delegate," said Rothberg, a graduate of The College of William and Mary's law school who moved to Alexandria in 1976. He is a past president of the Alexandria Young Democrats and serves on the board of the Alexandria Jaycees.

Rothberg also said his law practice deals in everyday matters of Virginia law--divorce, condominiums, property rights, for instance--and this has given him knowledge of state law that is the bread and butter of every legislative session.

Chabot, 32, a low-key speaker who got his law degree at the University of Virginia, also argues he has important experience in government.

As an undergraduate in Charlottesville, he was student council liaison to the General Assembly, lobbying for more education aid. He has worked on the Virginia campaigns of Edmund Muskie, George McGovern, Gov. Charles S. Robb and Lt. Gov. Richard Davis and as an aide to U.S. Sen. William Roth (R-Del.) and then-Sen. John Tunney (D-Calif.).

He holds various positions in the Fairfax County Democratic Party, including a seat on the Mount Vernon Democratic Committee, and is a member of the Fairfax Uniformed Officers Retirement Board, a county agency.

Chabot said his work as a partner in a law firm that deals in utilities regulation, environmental law and resources litigation has exposed him to problems like those facing Virginia and to the best solutions.

"We have cases all over the county in utility regulation. . . ," Chabot said. "The manner in which we regulate utilities is a major concern, and we've got to do something about it."

Chabot said the legislature will face some difficult decisions next year as it restructures programs hit by federal cuts--whether to continue them, scrap them or find money elsewhere. He argues that his experience in the federal government and law, as well as familiarity with Virginia politics, would help him make those decisions.

Rothberg's financial reports show he had raised $3,300 as of June 3, all of it in contributions of $100 or less, except for $200 from his parents. He had spent about $2,900.

In his door-to-door canvassing, Rothberg said, he has called at each of the more than 1,500 households where a resident voted in the 1981 Democratic primary.

Chabot said he is looking beyond the primary and is not concentrating on Democrats. "When I do a street, I do every house on the street," he said.

He has spent more than five times as much as Rothberg. As of June 3, he had raised about $7,500 in contributions, many of them larger than $100, and $1,700 in loans, his treasurer, Joel R. Cannon, said. Unpaid bills accounted for the remainder of the $14,700 spent.