Barack Obama became the Democratic nominee for president of the United States by being a candidate who happened to be black, rather than a black candidate.

His convention acceptance speech, which drove home the twin towers of his campaign — that he offered change from the Bush years and unity for the country — could have been, and much of its substance was, spoken by his much paler predecessors.

Obama’s nomination came 45 years to the day after Martin Luther King’s “I Have a Dream” speech which made the slain civil rights leader an American icon. Obama’s nomination is the embodiment of King’s vision that the United States would one day become a place where a black person can achieve any office, even the presidency.

He acknowledged the anniversary at the end of his speech but did not dwell on it, or even name Dr. King, in an effort to focus the national television audience’s attention on the presidency of George W. Bush and Obama’s contention John McCain would bring more of the same.

In fact, it was McCain, who almost seemed to take greater notice of the occasion, releasing a TV ad that aired in battleground states during the telecast of the Democratic convention in which the Republican said:

“Sen. Obama, this is truly a good day for America... How perfect that your nomination would come on this historic day. Tomorrow, we’ll be back at it. But tonight, senator, job well done.”

Actually, Obama — who has been criticized by some in the black community for not talking more about traditional civil rights issues in his campaign — used the speech to portray himself as the latest in a long line of Democratic leaders.

Rather than describing himself as a disciple of the late King, he reveled as the political descendent of Democratic icons Franklin D. Roosevelt and John F. Kennedy.

The speech with minor changes could have been given four years ago by 2004 Democratic nominee John Kerry and a number of other Democratic nominees in recent decades.

Like Kerry in 2004, Obama proclaimed his willingness to use force if necessary to protect U.S. interests, but said he preferred diplomacy, and promised to end the Iraq war “responsibly.”

His version of Kerry’s walking onto the stage with a salute to the American people and saying, “I’m John Kerry and I’m reporting for duty,” was to challenge voters who worry Democrats might not be tough enough on national security matters:

“Don’t tell me that Democrats won’t keep us safe.”

Polls show that Obama’s lack of foreign policy experience is cited by voters opposed to Obama or undecided about him as one of the major reasons for not backing him. Over the last several decades Democratic presidential candidates, even veterans like Kerry, have generally found themselves in the same boat and made similar appeals.

Like Bill Clinton in 1992, Obama promised a middle-class tax cut and a radical change in direction after years of Republican rule.

Like Al Gore in 2000, he said he would look out for the average Jill and Joe and not let them be victimized by the Republicans. Obama did not use the line that he was “for the people, not the powerful” that Gore, who spoke before him, coined in the 2000 campaign. But his plan to take a share of oil company profits and rebate them to consumers fit right in with that theme.

Like Dukakis in 1988, Obama focused his speech on the need for change to end a Republican rule that he said had made the country a worse place to live. Dukakis’ line that “the Reagan era is over and a new era is about to begin” could easily, with just a name change, come out of Obama’s mouth.

And Obama’s reference to King, although obviously more meaningful because he is African-American, could have just as easily come from any of the white Democratic nominees since 1964.

Racial harmony has been a centerpiece of Democratic campaigns since the 1960s, and Obama’s use of King’s words that “we cannot walk alone ... we cannot turn back” could just as easily come out of the mouths of Lyndon Johnson, Hubert Humphrey, George McGovern, Jimmy Carter, Walter Mondale, Dukakis, Clinton, Gore or Kerry.

Peter A. Brown, formerly the chief political writer for Scripps Howard, is the assistant director of the Quinnipiac University Polling Institute and a weekly columnist for The Wall Street Journal online.