Washington ? On Monday, just about the time word was spreading that Al Gore was going to endorse Howard Dean for the Democratic presidential nomination, Andrew Kohut, the respected pollster who runs the Pew Research Center for the People and the Press, released his latest survey showing “voter opinion is still fluid in the early Democratic primary states.”

Dean, the former Vermont governor, led Rep. Dick Gephardt of Missouri by 8 points in Iowa and Sen. John Kerry of Massachusetts by 14 points in New Hampshire, with 17 percent undecided in each state. But in South Carolina, the most contested state on the first multistate day of voting, Dean was running sixth, trailing Sen. John Edwards of North Carolina, retired Gen. Wesley Clark, Gephardt, Sen. Joe Lieberman of Connecticut and even activist Al Sharpton.

Kohut’s national poll of Democrats showed four candidates bunched within the margin of error — Dean, Clark, Lieberman and Gephardt — with none having more than 15 percent support and 23 percent saying they were undecided.

In the light of that survey and others like it, Gore’s decision to intervene early — and especially his call on Dean’s rivals to “close ranks” behind the governor — is one of the more eccentric developments in modern political history.

As a private citizen, Gore has as much right as anybody to express his preference. But as the former vice president and most recent presidential nominee, his obligations are different. Since he waged his valiant campaign and conceded with remarkable grace after the 36-day Florida recount ended in the Supreme Court, Gore has largely abandoned his role as titular leader of the Democratic Party.

For him now to intervene in a dramatic way in the choice of the next nominee is, at the least, a reversal of form — done with no consultation with other key players and with the same combination of secrecy and surprise as his decisions in his own campaign to change managers, to move headquarters and to pick Lieberman as his running mate.

Gore’s action changed the race and rattled Dean’s rivals, though all of them vowed in Tuesday night’s New Hampshire debate that they would carry the fight to the voters. With Gore running interference, Dean has the best blocker he could find to fend off attacks on his positions and his electability. The endorsement should boost Dean in Iowa, where Gephardt has been a real threat, and it may help with African-American voters in South Carolina and other states.

Some, however, may wonder how much confidence to place in Gore’s political judgment. This is the man, after all, who lost the White House in a time of peace and prosperity, a strategist who refused to permit President Clinton even to campaign for him in New Hampshire, West Virginia or Florida — all Clinton states, any one of which would have given Democrats the victory.

Gore said he had been impressed by Dean’s grass-roots support, and indeed, the campaign has been brilliant in mobilizing volunteers and contributors on a scale no one else has come close to matching. But Kohut’s survey shows that support is based on a very well-defined constituency.

As he put it, “Dean’s advantage is bolstered by his strong appeal to the well-educated liberal wing of the party in Iowa and New Hampshire. Nearly half of Dean’s Iowa supporters are college graduates and far more describe themselves as liberal (38 percent) than conservatives (17 percent).” The Dean supporters are notable, not only for the vehemence of their opposition to the Iraq War, but also for their support of gay marriage and for their variance from national norms of religiosity. Forty percent of the Dean supporters in New Hampshire, his strongest state, say they seldom or never attend church.

As Gore knows well, one of the great divides in 2000 was between regular churchgoers, who went heavily for Bush, and the less-churched, who voted Democratic. And Gore was a candidate, unlike Dean, who spoke openly and often about the role of religion in his life.

Thus far, despite his glowing notices, Dean has failed to dominate any of the Democratic candidate debates. On Tuesday, while basking in the Gore endorsement, he virtually disappeared for long periods, while long shots such as Dennis Kucinich made their rhetorical points. Dean’s great achievement has been not what he has done on stage with his rivals but in building his grass-roots organization. The best test of that organization’s prowess is still to come, starting in Iowa and New Hampshire and continuing in later primaries.

David Broder is a columnist for Washington Post Writers Group.