Careful observers of the international scene are aware of the latest developments in Canada. Wracked by internal dissension, centrifugal forces and other multisyllabic cliches, the recent talks aimed at writing a new Canadian constitution broke down a few days ago amid whispers that America's neighbor to the North might, perchance, disintegrate.

The sharpest of these observers, however, have noticed another up-welling of passion in Canada, one that has unified rather than fragmented. Those emotions revolve around the Montreal Expos.

Les Expos now stand at the top of the heap in the N.L. East, in search of the first Canadian pennant. Picture it: a World Series in the snow, with Bowie Kuhn shivering in the front row. By succeeding in the American pastime, the Expos may force 100 million Americans to do what no international crisis, no war, no referendum has ever done: notice Canada.

And if you think for a moment that the whole country is not behind the Expos, you are wrong. By hitting America where it counts--on the ball field--they can command televised respect without even instituting draft registration.

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The Expos have always had a character, a kind of discreet continental charm mixed with grittiness. For years, sportswriters took more notice of Montreal's fine cuisine and sidewalk cafes than the team itself. Before the Olympic Stadium was built, Jarry Park was a favorite target for written abuse.

But Jarry Park had its moments, too. Rusty Staub--dubbed "Le Grand Orange" by Francophones who adored his carrot-colored hair--provided patient fans with at least a few thrills. Gene Mauch, the greatest manager never to win a pennant, gave the baseball intelligentsia strategic gems to discuss in bistros.

Even the organist and the P.A. announcer got into the act, the former establishing a reputation as the best in the majors and the latter bouncing backup catcher John Bocabella's sonorous name off the tiny stadium's cheap steel seats ("Et maintenant, numero 12, Jahn...Boc...a..bellll...a).

Then Kenny Singleton went North and switch-hit his way into the coeurs of Montreal, Tim Foli brought spunk to the shortstop position, and Ron Hunt leaned into every ball hurled his way, setting a new record for being hit by pitches.

Those were the little things, the things that, together with the novelty of big-league baseball, allowed Les Expos to pour money into their farm system as fans poured through the turnstiles. A few years later, the system seems to have worked.

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Unlike so many other teams that float into the upper echelons, the Expos have still maintained their unrefined manner, their distinct character.

Any team that features Spaceman Bill Lee, outspoken Ron LeFlore, gutsy Gary Carter and the enigmatic Ellis Valentine will be an interesting assemblage. Any team managed by the inimitable Dick Williams, matched only by Billy Martin in the ranks of contentious skippers, will surely have a certain joie de vivre.

But the bottom line is the win column. And the Expos are winning, mostly behind a rotation consisting of Scott Sanderson, Steve Rogers, David Palmer, Bill Gullickson and Charlie Lea--a rotation which not so long ago labored for Memphis in Double-A ball.

LeFlore has snatched 90 bases, Rodney Scott has furnished additional speed, and farm products Larry Parrish and Warren Cromartie have hit consistently.

With Elias Sosa coming out of the bullpen to douse late-inning rallies, the Expos have so far been able to stave off opposition from the defending champion Pirates and the talented, well paid Phillies.

With a slim one-game lead, the Expos cannot afford to wax complacent. Nothing, however, can compare to the ordeal of last September, when the division crown narrowly eluded the squad which played 31 games in 28 days.

The deep pitching staff and a superhuman effort kept them close, but when the season boiled down to a crucial series with Philadelphia, the Expos' bats went flat.

Still, last fall's experience should stand Montreal in good stead this time around. The addition of LeFlore gives the offense the explosiveness it has lacked.

And the naysayers who predict Canada will crumble might be wise to wait--at least until after the World Series. You never know how a sporting victory can reverberate through politics.