Now and then, somebody comes up with a different way to run for Congress.

Listen to Cathy Long, front-runner in Saturday's special primary election for the seat left vacant by the Jan. 20 death of her husband, Rep. Gillis W. Long (D-La.), discourse in an interview on the issues of the day:

* The MX missile: "I have an idea on that, but I am not prepared to say what it is. There's really no reason for me to voice an opinion at this point."

* Abortion: "Only one person in the entire campaign has asked me about it, so I don't think we need to bring it up in this story."

* Deficit reduction: "If the best economic brains can't answer that question, I can't either right now."

* Toxic-waste disposal: "We have three hazardous waste sites in the district. Jock has said two have been cleaned up, but I don't think that's true. I need to find that out. It's one of the things I haven't had enough time to be briefed on." [The reference is to Long's principal opponent, Democratic state Rep. John (Jock) Scott.]

* Unemployment: "It is the No. 1 problem in the district . . . [but] I am not really prepared to take a stand on what we should do about it. I've got a lot of learning and listening to do. I'm already friendly with the leadership of the Congress, and I know they're going to help me."

If Long's positions seem vague, that's the idea.

"Let's face it, she is going to get elected this first time out as Mrs. Gillis Long and not as Cathy Long," said Carson Killen, administrative aide to the late representative and chief campaign strategist for his widow.

"Gillis Long had a 22 percent negative [rating in district voter surveys] in life and a 3 percent negative in death . . . . He's our big plus. He's the campaign manager in this campaign and probably the candidate, too. Why start from scratch if you don't have to?"

"Because the strategy assumes that the people of the 8th District are not bright," countered Scott, 37, who two weeks ago overcame his wariness about attacking a widow and began homing in on Long's mum's-the-word campaign style.

"If Cathy Long can't talk to us here, how can she talk for us in Washington?" asked Scott, who was state campaign coordinator for Sen. Gary Hart (D-Colo.) in last year's presidential primary.

Besides Long and Scott, two other Democrats and a Republican are running. Under Louisiana's nonpartisan primary system, all will appear on the same ballot. A candidate who receives 50 percent plus one vote Saturday is the winner. If no one does, the two top finishers will vie again May 4.

Long's poll numbers dipped under 50 percent for the first time last week. Killen predicted that the undecideds will put her over the top but added, "I'm glad the election is Saturday." Most observers here say they believe that a runoff would be treacherous. "The free ride would be over," one Long supporter said.

The 8th District crosses the midsection of Louisiana and is a microcosm of the state -- filled with sugar, rice and soybean farmers, blacks (34 percent of the voting population), Cajuns, rednecks and a labor union influence in the petrochemical industry. Unemployment is 12.5 percent, slightly above the state average.

The late Gillis Long was often accused of being too liberal for the district but served eight terms.

At least one Long has represented Louisiana in Washington for 54 years -- a dynasty that, given Sen. Russell B. Long's decision not to seek reelection in 1986, would be broken if Cathy Long didn't win her husband's seat. Gillis and Russell were cousins.

Dynasties have their advantages. On Saturday, the foot soldiers of the Gillis Long machine -- about 2,000 earning $50 a head -- will help get out the vote. In a small turnout, they could be the difference.

Long has spent $600,000 on the race -- about $450,000 of it borrowed against proceeds from her husband's life insurance. After the election she will be able to repay the bulk of the loans with $410,000 that her husband had amassed in a campaign kitty and that she will inherit.