Six months before his 1984 reelection, U.S. Sen. John W. Warner (R-Va.) had a formidable campaign strategy in hand: a $1 million war chest, much of it raised from Washington's many political action committees.

A number of Virginia Democrats readily acknowledged that the prospect of running against a popular Republican who had $1 million in the bank was enough to scare off their party's best prospects.

The result was Warner's landslide victory over Edythe Harrison, a little-known former state legisla- tor from Norfolk.

Warner's reelection fueled the arguments of many in Virginia who complain that the cost of winning a seat in Congress is too high and say that limits should be placed on giving by PACs.

Warner, who received $693,913 from PACs during the 1984 campaign, disagrees, and this week he is expected to join others in the Senate fighting a measure introduced by Sen. David L. Boren (D-Okla.) that would sharply restrict PAC contributions in congressional elections.

Sen. Charles McC. Mathias Jr. (R-Md.), a supporter of public financing of campaigns who is not running for reelection, also has objections to the Boren measure, according to a Mathias aide.

Sen. Paul S. Sarbanes (D-Md.), who received $465,487 in PAC contributions in his 1982 campaign, supports the restriction on PAC contributions. Sen. Paul S. Trible (R-Va.), who got $671,016 in PAC funds for his 1982 campaign, was out of town and could not be reached for comment, according to his spokesman.

The Senate is scheduled to debate the Boren measure today, when it returns from Thanksgiving recess, and vote on it tomorrow. The measure will be offered as an amendment to an unrelated radioactive waste bill.

The Boren amendment would limit total PAC contributions in all congressional campaigns. A candidate in a House race could receive a total of $100,000, plus $25,000 if there are contests in the primary and general elections. The limit in Senate races would range from $175,000 to $750,000, depending on the population of the state. Virginia's limit would be about $350,000 and Maryland's about $280,000.

The Boren measure, which would take effect in the 1988 elections, would lower from $5,000 to $3,000 the maximum that any PAC can give to a congressional candidate. It would raise the limit for individual donations from $1,000 to $1,500.

Common Cause, which supports limits on PAC giving, says candidates for Congress are increasingly dependent on PACs for campaign financing. In 1984, House and Senate candidates received more than $100 million from 4,000 PACs. A decade earlier, congressional candidates received only $12.5 million from 608 PACs.

During the first six months of this year, the 28 incumbent senators facing reelection next year received an average of $208,194 in PAC funds. That was more than twice the average of $96,528 in PAC funds received during the same period in 1983.

Boren, Sen. Barry Goldwater (R-Ariz.) and other supporters of the bill have argued that the rapid growth of PAC contributions has undermined the integrity of the election process by giving, or appearing to give, too much influence to special interests.

Warner disagrees, according to his administrative assistant, Andrew F. Wahlquist. The aide said that the senator believes that PACs are not "faceless special interest groups" but are made up of men and women who want to participate in the political process. Some people would rather donate money, he suggested, while others would rather donate time. Asked Wahlquist, "Is the next suggestion to limit the amount of time that can be donated by the AFL-CIO" or other groups of special interest volunteers?

Warner's assistant said the Virginia senator "believes the present system works well" because PAC contributions must be reported to the Federal Election Commission. "He likes the system and thinks it works well. He feels if it ain't broke, don't fix it."

Mathias, chairman of the Rules Committee, has been an outspoken critic of the current campaign system, saying that something must be done to curb the influence of the rich and powerful. He has introduced a bill that would establish limited public campaign financing, and the Rules Committee has begun a series of hearings on the measure.

A Mathias aide said the Republican senator wants to make sure that complicated campaign financing legislation receives close consideration at the committee level before going to the full Senate for a vote. Boren is bypassing the Rules Committee and taking his bill straight to the floor by offering it as an amendment to another bill.