Down in Tampa, the case against Congress is snowballing. THRO, the movement to Throw the Hypocritical Rascals Out, got 21 trays of mail last week. A mailman counted one of them and came up with 800 letters. The size of the donations is increasing, too. It used to be about $10. Now it's closer to $20. A 90-year-old man sent a $100 bill. One fan sent a $5,000 check. The phone rings nonstop with people terribly enthusiastic about the idea of seeing all incumbents defeated. The volunteer who handles the calls has to take it off the hook when she needs to use the facilities.

From an Albuquerque woman's letter to THRO:

We have desperately needed a "Pied Piper" for so very long. I cannot believe what is going on anymore. One of my great outrages is so much money going to other countries while we fall apart ... Politics stinks. I think we should run this country like a business. The American way is "Hire & Fire."

How much money have they taken in? They don't know. Maybe $400,000, perhaps a half-million by now. The funds come in, they buy more ads. They've run 172 of these allegation-stuffed broadsides since THRO founder Jack Gargan started things going with $45,000 of his own money this summer.

The headline at the top of the ad is the war cry from the movie "Network": "I'm mad as hell and I'm not going to take it anymore." The accompanying photo of Gargan in an open-necked shirt doesn't look particularly angry; it's more like he's about to cry. The text covers the sins you might expect: the national debt, congressional raises, the influence of political action committees, the savings and loan boondoggle. At the bottom, there's a reply coupon.

After the election Gargan promises a full accounting of all funds raised. But he points out that while he hopes to get his $45,000 back eventually, no one is drawing a dime from this operation, including him. The handful of staff running the office (really a house that Gargan owns) is working for love, not money.

Donna -- except for Gargan, no one who works for THRO gives out a last name -- brought along her own stapler, calculator and Magic Marker when she signed up six weeks ago. "I read about it in the Tampa Tribune," she says. "I said to my husband, 'Boy, someone's doing what should have been done.' I said to Len, that's my husband, 'I'm going to go work on this.' I've been here all except for three days since. I've put my life on hold. I'm just a housewife. My husband works on a ship, so he's barely home. And when he does come home now, he's ignored."

And where is commander-in-chief Gargan in the midst of all this? England and Ireland, where he had some personal and professional business that was arranged long ago and couldn't be put off.

"People are finally realizing their senator and representative are just as rotten as the rest of them, for the most part, and it's hitting them in the pocketbook," Gargan says when he is reached in London.

"One year ago I couldn't have pulled this off. Now, with the S&L scam -- every time you open the paper it costs more -- and the HUD scam, and the moral turpitude that doesn't get punished ... The public has had it. They just didn't know how to vent their anger. I'm giving them a way -- on Nov. 6 when they pull that lever. And for the congressmen who have no opposition whatsoever, I want them to pick a local hero and write his or her name in. At worst, it's going to make a strong statement that they don't like the guy in there."

This isn't Gargan's first brush with fame. Now retired, he's founder and past president of the International Association of Registered Financial Planners. In 1984, a rival group, the International Association for Financial Planning, accepted for membership Boris "Bo" Regaard. Bo happened to be Gargan's dog. "He was as cute a little dog as you'd ever want to see, but not quite as cute as to be a financial planner," says Gargan. The IAFP was appropriately embarrassed.

This time, Gargan's out for much higher stakes. He's been helped immeasurably by the travails of Congress over the past couple of weeks, as the government has flirted with shutdown and paralysis. Ridicule, never far from the tongue when considering Congress in the best of times, has become the operative lingo. "I love it, I love it, I love it," says Gargan. "The budget deadlock underlines everything I'm saying. It shows how out of touch with their constituency these clowns are."

In '88, in the House, only seven incumbents were defeated. Gargan cites a political analyst who told him that "at the very most, 25 representatives this year had even the slightest opposition and could be subject to losing. And no way all 25 would lose. So I would say 14. Twice what it was before."

That's what he realistically expects; but he won't be satisfied unless at least 10 percent of the House falls -- 43 of them. "And I wouldn't be surprised if 120 were blown out this election. Or more. You should see the mail."

From an Ohio man's letter:

I thank God for you and you are always in my prayers. I am 55 years of age and am on SSI but this is the best $10 I will ever spend. Please don't give up, we who want to help are out here by the thousands.

It sounds, at least, like a small-scale crusade, but two inside-the-Beltway political experts were less than convinced. For one thing, as Gargan admits, few of the congressional races are anywhere near close.

"It's very difficult to throw the 'bums' out at this stage because the system is structurally set up against it. In many cases the real election is already over, because in a whole number of states the real election is the primary," says James A. Thurber, director of the Center for Congressional and Presidential Studies at American University.

Furthermore, when it comes down to selecting a person who doesn't have any experience, as opposed to the guy who's already in there and who has a lot more money to buy advertising time to get his name across, Thurber feels they'll overwhelmingly go for the evil they know.

There will be two ways to measure whether the THRO sentiment is really widespread. First, look at the House returns for the percentage of those representatives seeking election who actually achieve it. From 1950 to the present, the average is 93 percent. Only four times has it dropped below 90 percent: 1958 (89.9), 1964 (86.6), 1966 (88.1), 1974 (87.7).

Lower than 90 percent, Thurber says, would be remarkable. "If you get anything above 40 people defeated in the general election, then you can say there's a true anti-incumbent feeling out there," he says.

A second method involves House elections won by 60 percent or more of the vote. In 1988, a record 88.5 percent of the incumbents managed to achieve this. The lowest it's been over the last 34 years was in 1964, when the percentage fell to 58.5. This year, a drop below 75 percent would satisfy Thurber that's there's at least a minor revolution brewing.

THRO already, however, represents a new stage in anti-government attitudes. "In 1974, there was an anti-incumbency feeling in the nation as a result of Watergate and the Vietnam war, but there wasn't a guy out there running ads asking for money to throw the bums out. I can't say it's unprecedented, but it hasn't happened in the modern period," says Thurber.

Another close watcher of these phenomena is Thomas E. Mann, director of governmental studies at the Brookings Institution. THRO, he agrees, is something different. "Usually, you don't get an across-the-board, bipartisan, throw-the-rascals-out movement. It typically is launched by one of the political parties, and typically in a midterm election it's against the party of the president."

But he also points out that the average senator raises more money in the same small contributions from one state than Gargan is drawing from the whole country. The state of the economy, Mann argues, is much more on the public's mind than any frustration at how poorly the wheels of government spin.

In the last three congressional elections, an incumbent practically had to be accused of a crime to lose. The Reagan boom was in full flower, and "Don't Rock the Boat" was the prevailing sentiment. Now, says Mann, "There's more angst. There's middling discontent. But that's a far cry from an uprising in the electorate."

The combination of the term-limitation movement and things like THRO "have the effect of scaring politicians," says Mann. "It may lead to some individual upsets, and it may embarrass the Congress into instituting some reforms that are called for. But I worry a lot about the way in which we're fostering this cynicism toward our national political institutions. We've got problems, but let's deal with them in a fair and balanced way. Let's not constantly be taking cheap shots."

If there really is an across-the-board revolt going on, he would expect more Democratic incumbents to lose than Republicans. "I would be shocked by that," he says. And while he expects the margins of victory to sink, "I will be surprised if a total of more than 20 or 25 incumbents in the House are defeated."

William Walton Mims, editor of the Edgefield Advertiser, the oldest newspaper in South Carolina, liked THRO's advertisement so much that he ran it for free. "It fits neatly into my editorial policy, which is adversarial," says Mims. "I'm always ready to champion someone who is exposing the rascals at the crime center of the world."

The editor notes that the first member of Congress ever to be censured was from Edgefield, for the crime of whipping a member from Massachusetts. Not such a bad precedent, you can hear Mims arguing. "We're continually having to contend with the Saddam Hussein type," he says, "particularly in the person of Strom Thurmond" -- the South Carolina senator and a longtime antagonist of the paper.

In Brooksville, Fla., north of THRO headquarters in Tampa, there's a billboard that says, "Save America, Reelect Nobody." "That had nothing to do with Jack," says THRO volunteer Donna. "But we got 50 letters about it." Truck drivers in Texas are supposedly putting black ribbons on their cabs. A sporadic "Read My Lights" movement was said to be starting, at least in Maine; THRO supporters were to keep their headlights on during the day. "Recycle Congress," people write on their checks in the little spot for the message. "Go for it, tighten the noose, put the screws on, here's more ammunition, let's keep stoking the fire," recites Donna in summarizing the general drift. The movement is building its own mythology.

The congressional representative from Tampa is Democrat Sam Gibbons. His press secretary, Lisa Garcia, downplayed any local effect THRO was having. "As far as we can tell he does have support in the area, and has gotten support nationwide, but for the most part people feel it's irresponsible to throw every incumbent out of office," she says. "It's not something we're overwhelmingly concerned with, because we're not in a tight race this time."

Throwing the bums out is just the beginning, of course. The real aim here is the highly controversial remedy of term limitation, of which Gargan is a fervent supporter and whom Gibbons, in office since President Kennedy was alive, presumably is not.

"I'd like to see one six-year term," Gargan says. "Maybe the public would like two four-year terms. What we're after is that once the public understands the power they have at the polls, then they can hold these guys' feet to the fire."

Wrote a Missouri man:

I had made the decision several months ago to never vote again, since the politicians were going to do what they want, instead of what the people want ... However, I plan to change my mind and vote one more time to get the bastards out of office. If this doesn't work, I'll just have to take care of my family the best I can, which means I will report no income and pay no taxes!