The campaign against the accord comes late in the game - the first ministers are to meet June 2 to consider the formal wording of the deal, hammered out last week. But what was once a barely discernible groundswell of social policy groups and federalists has now begun to coalesce around a self-styled ''Group of 43'' lawyers, academics, and public figures.

Trudeau's criticisms, first printed in the Toronto Star and Montreal's La Presse, appear to have accomplished two things. First, by his stature and francophone pedigree, Trudeau has given opponents of the deal greater credibility and profile than before.

Second, his harsh language has staked out the intemperate limits of the debate. Meech Lake advocates hope this will backfire; it is more likely to provide a shield for other critics of the agreement, allowing them to appear more moderate by comparison.

The counterattack from the Prime Minister and premiers' offices has been aimed at portraying him as ''yesterday's man,'' clinging arrogantly to an outdated vision of the country. But beyond vague assertions to the effect that ''Quebec has changed,'' little has been said to demonstrate how it has changed, or whether such changes are material to the argument.

Trudeau's timing was carefully considered. By waiting nearly a month after the agreement, speaking out only after mounting calls from critics of the accord for his voice to be heard, and issuing a mildly worded teaser speech earlier last month in Toronto, he was able to give something of the appearance of having been drafted.

Despite splits in all three federal caucuses, most grievously in the Liberals, there is little likelihood of stopping ratification of the accord in Parliament. No federal party can risk being branded as anti-Quebec.

The focus of efforts instead will be on the provinces, and in particular two: - Manitoba, whose NDP Premier Howard Pawley is pressing for an amendment to the agreement's opting-out clause stipulating that ''national objectives'' be ''defined by Parliament.'' That amendment runs smack into attempts by Quebec to delete the requirement that opted-out programs meet any national criterion at all. - Ontario, where Liberal David Peterson's NDP partners in the two-year-old minority government are expected to come under intense pressure to oppose the deal, along with the Opposition Tories.

Critics of Meech Lake are downplaying expectations of any open collapse of agreement at the June 2 meeting itself. But they hope ensuing public hearings would offer any premier with misgivings about what he had signed a face-saving way to back out, perhaps by demanding an amendment that would unravel the carefully wrought lacework of the accord. In any event, the longer the ratification process is delayed, the greater the chances of the deal going under.

One potential new dynamic is the coming Ontario election. Sniffing a possible vote-catcher, Conservative Leader Larry Grossman has been emboldened in recent days to speak more strongly against the accord than his previous cautious questions.

While Peterson has been firm in his support of the agreement, he has announced he will hold public hearings before ratification. If he senses opinion in traditionally federalist Ontario swinging against the deal, he will face a tricky political quandary if an election intervenes before the ratification process is complete.