"The thing you have to remember," said one veteran Masschusetts politician, who had just watched Edward J. King debate Francis W. Hatch in the forum of the new John F. Kennedy School of Government at Harvard, "is that Massachusetts is the 10th largest state in the nation and one of these men is going to be its governor."

That is a prospect that is going down hard in the Commonwealth. Massachusetts can accept anything in the governship from a well-bred gentleman like Leverett Saltonstall to a brilliant scoundrel like James Michael Curley. But whether statesmen or scalawags, massachusetts expects little class.

What it did not expect this year was to be facing a choice between King, a conservative Democrat, and Hatch, a progressive Republican, who have both reached the age of 53 without acquiring the sort of political finesse Massachusetts looks for in a governor.

The original script for 1978 called for King to lose to Gov. Michael J. Dukakis in the Democratic primary and Hatch to succumb meekly in the general election.

But when the returns were counted in September, it turned out that both Dukakis and the polisters should have paide more attention to the rich abundance of "Dump the Duke" yard signs and billnoards that sprang up over the summer.

Dukakis, who had parlayed a repulation for personal integrity and austerity and an innovative urban revitalization program into a position of national leadership among the governors, was unceremoniously cut down in the primary.

Kin triumphed with a platform that seemed at first glance a contradiction of Massachusetts' liberal dogma: a Proposition 13-type slash in spending and taxation; reimposition of capital punishment; a cutoff of Medicaid funds for abortions and an increase in the drinking age from 18 to 21.

At second glance, it seemed even worse to many of the state's liberals, and in the week after the primarly, Hatch, the sacrifical lamb, suddenly was inundated with promises of support from appalled liberal Democrats.

National Committeeman Jerome Grossman, defeated gubernatorial candidate Barbara Ackermann (who had rained votes from Dukakis on the left), and half a dozen of the most liberal Democrats in the legislature jumped ship and endorsed Hatch.

"For a few days there," said one Hatch worker," we had so many Democrats in here the Republicans were beginning to feel uncomfortable."

But if the liberal defectors were flooding to Hatch, conservatives in both parties were rallying around King. Auto dealer Peter Fuller and financier Lloyd Waring, both Republican donors, swung behind King. Riding the crest of the tax revolt, he surged to a 23-point lead in the first post-primary polls.

Enter, The Boston GLobe. In a series of investigative articles, The Globe did what no one had bothered to do during the primary. It checked King's record. It found the onetime professional football tackle, whose work as executive director of the Massachusetts Port Authority (operator of Logan Airport) it had praised at the time, had some remarkably free-spending habits for a tax-cutter.

Massport turned a growing profit during King's years, and the director was lavish in his entertainment. During his last two years there, the agency ran up $148,000 in food and entertainment expenses on 54 officials' credit cards. Somehow, they managed to spend more than $100,000 at three Boston restaurants and $173,000 for catered meals.

King also negotiated $103,000 severance pay for himself when he was fired after 15 years, largely because his aggressive airport expandion policies and high-handed managerial style had created too much political controversy.

THe Globe reporting has provided the substance of Hatch's campaign -- and it has been effective. King's early lead has melted away and the race is now regarded as a tossup.

In their debate the other night, Hatch said in his opening statement, "Ed King ran Massport . . . with a credit card for the boys in one hand and the other hand on the throttle of a bulldozer . . . You can't run the state the way Ed King ran airport. It just doesn't work that way."

To the chagrin of his supporters, however, Hatch was unable to score any real points off the often-inarticulate King once the debate began. The two men quarreled interminably about consultants' estimates of potential welfare savings and left whatever remained of their radio audience in total bafflement.

The same thing is true of Hatch's campaign. His TV spots -- focusing on the Massport charges -- have clobbered King's credibility. But nothing he says seems to give anyone a strong reason to vote for Frank Hatch.

In background and style, the two men are at opposite ends of the Massschusetts social scale. King is blue-collar Catholic; Hatdh is bluebood Yankee. King misses no opportunity to remind the voters of that fact. In the debate, he remarked that Hatch has no crime program. He lives on an estate in Beverly Farms, with his inherited millions, and just doesn't see what crime is doing to the average person."

A new King commercial this week used serial photos of the Hatch estate to sharpen the social conflict -- cussing Hatch's wife, Bambi, an heiress in her own right, to complain that if any burglars were watching, King was certainly showing them the best way to break in.

Hatch has been a full-time legislator for almost 20 years, the leader of his party's tiny minority in the State House of Representatives for almost half that time. Somehow, he has come through the experience almost devoid of political skills. A tall, thin man, he is noticeably reticent in his personal dealings. He has largely financed his own campaign to spare himself the discomfort of asking others for money and -- other GOP officials says -- has let some conservative Republicans drift into the King camp because of his failure to make them feel wanted.

Hatch wins praise from liberals in both parties by his dogged determination to stay with his own views on abortion, capital punishment and other social issues -- and his willingness to throw cold water on King's tax-cut promises, even though the voters plainly want to be promised relief. But a leading Democrat remarked that "if the Republicans were running Frank Sargent (Dukakis' GOP predecessor) instead of Frank Hatch, the race would be over."

If Republicans are worried that their candidate may fail to capitalize on his opportunity, many Democrats have just the opposite fear. They are worried about what will happen if King wins.

Dukakis ended many of the more flagrant patronage abuses in the state house, and while that probably cost him politically, many of the younger Democrats would hate to see the old wide-open ways return Nonetheless, there is a rallying around King by mnay of the elements of the democratic coalition. Led by state employes (who had may fights with Dukakis) and construction workers (who remember King's penchant for building at Massport), organized labor has given him its endorsement. So have some Democratic officials, but Sen. Edward M. Kennedy (D-Mass) and most of the other members of the state ticket are keeping their distance.

One who cannot is Lt. Gov. Thomas P. O'neill Ill, who is nominated separately from the governor but is backeted with him as an entry in the general election.

O'Neill reportedly considered quitting the ticket when King defeated Dukakis, but reportedly was disuaded by his father House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass).

The O'Neill have secured endorsements for King from all but one member of the Massachusetts Democratic congressional delegation. The other day, Tom O'Neill produced 22 Democratic mayors who endorsed King on the understanding that, somehow, despite his economy pledges, he would not cut off Dukakis' much-admired urban aid program.

Young O'Neill is conducting a fervent campaign to "soften" King's hard-line image on the social and fiscal issues and appears to be having some success.

But the skepticism runs deep. The best clue to how Massachusetts politicians feel about both gubernatorial candidates is the length of the list of people -- Dukakis among them -- already lining up to run for governor in 1982.