SPRINGFIELD, MASS. -- It's doubtful that in the excitement of the summit meetings President Bush paid much notice to what happened here last weekend. But the collapse of Massachusetts Gov. Michael Dukakis' political dynasty, dramatized by the events at the state Democratic convention, illustrates the risks Bush is taking in tying his most vital foreign policy decisions to the personal fate of Soviet President Mikhail Gorbachev.

Two years ago, the man every Massachusetts pol calls ''Michael'' dominated politics here as completely as Gorbachev then controlled the Kremlin. Last weekend, his lieutenant governor, Evelyn Murphy, lost the convention endorsement for governor to former attorney general Francis X. Bellotti, largely because the delegates thought she was too closely tied to Dukakis to be able to win in November.

To underline the message, the delegates gave enough votes to Boston University president (on leave) John H. Silber to qualify him to meet Bellotti and Murphy in the September primary. Silber is a conservative Democrat who has proudly proclaimed that he voted for Bush against Dukakis.

What turned the tables was the slide of the New England economy -- which left Dukakis struggling with huge budget deficits and demanding tax increases, as voters' concerns about making mortgage payments and meeting the other bills increased.

Suddenly, the liberal programs that had been all the rage in the days of the ''Massachusetts Miracle'' became an albatross his own supporters would not carry. A convention dominated by teachers, public employees, politicians and issue activists rejected the legacy and political heir of the man who had governed Massachusetts longer than anyone else in its history and who had led the Democrats' quest for the White House less than two years ago.

In terms of personality, as Sen. Lloyd Bentsen (D-Texas) might say, Michael Dukakis is no Mikhail Gorbachev. But he is, like Gorbachev, a man who completely dominated a one-party state and pushed relentlessly for programmatic and process reforms. And when the economy unraveled under him, the people and the politicians turned and savaged him.

Bush has chosen to ignore the possibility that a similar fate could be unfolding for his favorite negotiating partner. Throughout the Washington and Camp David meetings, the American president labored to make Gorbachev look good at home -- repeatedly rejecting the idea that the tailspin in the Soviet economy altered the terms of the discussions.

That has been Bush's attitude toward Gorbachev from the start. Five years ago last March, when he met Gorbachev for the first time at the funeral of Konstantin Chernenko, then-Vice President Bush said, ''If there ever was a time when we could move forward with progress in the last few years, I'd say that this is a good time for that.''

In his first meeting as president with the Soviet leader, last December at Malta, Bush reassured him, ''You are dealing with an administration that wants to see the success of what you are doing.''

And last week, at the Washington summit, Bush once again underlined his faith in Gorbachev, telling him that ''I firmly believe, as you have said, that there is no turning back from the path you have chosen.''

His investment in the Soviet leader now outstrips, in fervor and in significance, his personal and policy commitment to any of the leaders of the West. Bush has been generous in his acts of friendship to Thatcher and Kohl, to Mulroney and Kaifu and Mitterrand -- but none of them has received the time, the attention and the flattery he has lavished on Gorbachev.

The evidence is lacking that Gorbachev, for his part, in any way sentimentalizes his relationship with Bush. The authors of the new book, ''Gorbachev: Heretic in the Kremlin,'' Dusko Doder and Louise Branson, formerly Moscow correspondents for The Washington Post and the Sunday Times of London, write that Gorbachev ''trusted Bush no more than Bush trusted him. But he needed the American President's goodwill. . . .''

Speaking of the concessions Gorbachev has offered over the last five years, they observe: ''All these moves have been calculated. Gorbachev knew that the Kremlin's global position was weakened. He has been engaged in a rebuilding of Soviet society -- and thus of Soviet power -- and has been ready to pay the price to gain long-term goals. If successful, he expects a revival of Soviet power.''

No one with an ounce of realism can object to a Soviet leader's setting that as his objective. But if Gorbachev is playing a game whose payoff will come after Bush has left the White House, it is essential that American policy have a goal more significant and more likely of accomplishment than merely keeping Gorbachev in power.

The spectacle in Springfield is a reminder -- if one is needed -- that ambitious goals and seeming popularity cannot survive an economic collapse. Boston and Worcester are a lot more prosperous than Moscow and Leningrad. If Bush wouldn't bet his domestic policy on Michael Dukakis, should he bet his foreign policy on Mikhail Gorbachev?