Worcester, Mass. ? Last Friday night, as he has so often before in his almost 40-year Senate career, Ted Kennedy stood before hundreds of the faithful at the Massachusetts Democratic convention, giving them the message.

Once again, he told them that their commonwealth and their party had the historic mission to provide leadership that would “bring the American dream to every family and every child,” to assure people “a fair wage and a secure pension, good schools, clean water and clean air.”

But this time, his task was to convince them that the man who could do this, “a strong American leader in each of these causes, a powerful, powerful national voice for the Democratic Party,” is none other than his junior partner for the past 18 years, Sen. John F. Kerry.

In introducing Kerry, Kennedy praised him so lavishly that audience members might have been reminded of that classic line from colonial Massachusetts: “Prithee, John, why do you not speak for yourself?” And when Kerry did, the spontaneous roars of agreement that Kennedy had evoked turned sporadic and labored. Reading a version of the standard stump speech he has delivered in recent months to other Democratic gatherings from Florida to California, Kerry was hampered by a balky TelePrompTer and, as he said later, “never found my rhythm.”

What comes easily to Kennedy does not to Kerry. That is part of the problem that lurks for the 58-year-old senator tall, handsome, battle-tested, wealthy and in the eyes of many colleagues, wise as he prepares to be the latest Massachusetts Democrat to test the presidential waters.

Were it not for Kennedy’s political bulk, Kerry would be regarded as a Democratic star. He knows foreign policy as well as anyone in the potential Democratic field with the possible exception of Al Gore. After leading the successful Senate fight to stop drilling in the Arctic National Wildlife Refuge, he can match environmental credentials with anyone Gore included. Six years ago, running for a third term, he beat the strongest Massachusetts Republican candidate in modern times, former Gov. William Weld. This year, Republicans have found no officeholder willing to challenge him. Kerry’s re-election television ads in Boston will reach voters in populous southern New Hampshire. And he will have the luxury of campaigning for, financing and helping staff other Democratic candidates around the country, especially in other early presidential battlegrounds such as Iowa and South Carolina.

But because of Kennedy’s seniority in the Senate, his activist staff and his automatic media coverage, Kerry will be starting from scratch in terms of national recognition. On most issues that make headlines, “Ted just doesn’t leave much room for John,” one Senate colleague said.

Kerry has one other problem: Michael Dukakis, with whom he served as lieutenant governor for two years, just before he won his Senate seat in 1984. Dukakis lost a presidential race to the elder George Bush that Democrats thought he should have won, deepening the belief in much of the party that upright, uptight liberals from the northern tier (McGovern, Mondale, Dukakis) cannot put together 270 electoral votes to win the White House.

Kerry hopes to combat that notion in part by telling the country of his notable Vietnam War record, which includes a Silver Star for gallantry in action on a Mekong River Navy gunboat. Unlike many of his contemporaries, he volunteered for service in Vietnam after graduating from Yale, then came home to lead the Vietnam Veterans Against the War in their effort to end the hostilities.

In a video shown at the convention but clearly designed for a national campaign, you see the young John Kerry in both roles a combat officer and an anti-war protester, someone who bridges the great gap of his generation.

There is every reason to think that if the war on terrorism is sputtering next year, as it seems to be right now, Kerry will not hesitate to question the strategy that President Bush has followed. Kerry was prescient in some of his early warnings about the terrorist threat and his war record gives him a degree of immunity from counterattack.

But Kerry is also a man who opposes the death penalty, wants to restrict access to guns and voted against the resolution approving the start of ground operations against Saddam Hussein in 1991 just what you would expect from Ted Kennedy’s partner and Michael Dukakis’ running mate, the Republicans will surely say.

Kerry is a serious man whose approach to the presidential race has been, in the judgment of one former Clinton-Gore strategist, “more thorough and professional than that of anyone else in the field.” He has never gained a fraction of the affection his home-state Democrats lavish on Kennedy, but increasingly, he has earned their respect. And they like having a contender once again.

David Broder is a columnist for Washington Post Writers Group.