Opposition Democrats detailed plans Tuesday for their national nominating convention, which will be held in Boston later this month. Republicans are also gearing up for their national convention in New York at the end of August.

Public opinion polls suggest a lot of Americans still do not know Senator John Kerry very well, even though he will be officially nominated as the Democrats candidate for president on July 29.

So Democratic Party Chairman Terry McAuliffe says the focus of the four-day convention beginning July 26 in Boston will be on re-introducing Senator Kerry and his vice presidential running mate, Senator John Edwards, to the American people.

"And we will use those four days in Boston to introduce to America John Kerry and John Edwards to talk about their backgrounds, their strengths and their vision for what they are going to do to get this country moving again," he explained. "The theme of the 2004 Democratic Convention in Boston is stronger at home and respected in the world."

Senators Kerry and Edwards will give the main speeches at the Democratic convention.

Other prominent speakers include former Presidents Jimmy Carter and Bill Clinton and former Vice President Al Gore. In addition, there will be a tribute to longtime Massachusetts Senator Ted Kennedy.

Republicans are gearing up for their own four-day convention at the end of August in New York City. Their list of prime speakers includes California Governor Arnold Schwarzenegger, Arizona Senator John McCain, former New York Mayor Rudy Giuliani and Vice President Dick Cheney. President Bush will speak when he accepts re-nomination for a second term on the final night of the convention on September 2.

The president and his Republican supporters continue to emphasize the Bush administration's record on terrorism and keeping the country safe.

President Bush again made prominent mention of the issue during a campaign visit to Michigan on Tuesday. "We have captured or killed many key leaders of the al-Qaida network. We will stay on the hunt until justice is served and America is safe," Mr. Bush noted.

American political conventions date back to the 1830s and brought party activists together to nominate presidential candidates for more than 100 years. But American University presidential historian Allan Lichtman says the role of the conventions began to change in the mid-20th Century.

"But really, during the last 50 years or so, conventions have not nominated the presidential candidates," he explained. "The presidential candidates have instead been nominated mostly in primary elections, particularly over the last 30 years. So conventions no longer nominate candidates."

In the modern era of conventions, party activists and delegates now come together to rally behind a candidate chosen through the lengthy series of state primaries and caucuses.

Washington-based political analyst Stuart Rothenberg says the main role the conventions now perform is to act as a sort of four-day broadcast advertisement for the party nominees.

"These are now media events," he added. "They are opportunities for the presidential candidate, not for the party, but for the presidential candidate to showcase himself and his ticket and to deliver the message that he wants that will ultimately be the general election message."

But because the modern political convention is so predictable and scripted, experts say political conventions have less impact on voters than they used to.

As a result, the major broadcast television networks now show much less of the four-day conventions than they did years ago, leaving much of the live coverage to cable news networks that draw much smaller audiences.