VOA标准英语2008年-US Presidential Candidates Prepare to Announce（在线收听）

Sen. Barack Obama walks to a car after a stop in Saint Paul, Minnesota, 7 Aug 2008

Public opinion polls give Democrat Barack Obama a narrow lead over Republican John McCain, so the upcoming conventions are important for both presumptive nominees.

President of the Pew Research Center Andrew Kohut says many voters do not pay much attention to the presidential race until the party conventions.

"This is a very important time because people get to see these candidates up close, and they recognize that it is only a relatively short run until they have to make a decision," he said. "And for McCain it could be a period of time where he really gets an advantage in terms of coverage and exposure, which he has not had over the course of this campaign yet."

The Democrats hold their convention in Denver, Colorado, the last week of August. The Republicans hold theirs the following week in Minneapolis-St. Paul, Minnesota.

Both candidates will be looking for a post convention bounce, or boost, in public opinion polls that will carry them into the general-election campaign between September and the election on November 4.

Norman Ornstein, a political scholar at the American Enterprise Institute in Washington, expects the presidential race to remain close and says both presumptive nominees have challenges at their respective conventions.

"And it is likely to stay that way because this is an election that in effect is about whether Obama can get over the threshold of acceptability at a time when people want change," he said. "And McCain is not the incumbent, but he is much more closely identified as the status quo."

Both contenders are expected to announce vice presidential running mates before the conventions begin. Neither candidate has given any strong indications as to who his running mate will be.

The four-day political conventions will give both Obama and McCain a chance to re-introduce themselves to the voting public, and to cast their opponent in negative terms.

"There is a truism in American politics, which is that the candidate who is able to define himself and define his opponent first wins the election," said Peter Brown, who does polling on the presidential race for Quinnipiac University in Connecticut. "This is an election that is about Senator Obama, and the question is who will be able to define Senator Obama for these voters we are talking about first and better, Senator Obama or Senator McCain."
　

Sen. John McCain makes a statement to reporters in Wilmington, Ohio, 7 Aug 2008

Senator McCain faces the challenge of putting some political distance between himself and President Bush, who continues to get low public-approval ratings in voter surveys.

But Senator Obama has issues as well. Pollster Andrew Kohut told VOA's Press Conference USA program that Obama is still having difficulty in winning over some supporters of former Democratic rival Hillary Clinton.

"Hillary Clinton supporters are still not fully onboard with Barack Obama," he said. "Just 72 percent of Clinton supporters say they are going to vote for Obama. Eighty-five or 86 percent of the supporters of McCain's former opponents are with him. So, Obama has not quite closed the deal."

Senator Clinton is getting a prominent speaking role at the Democratic convention, as is her husband, former President Bill Clinton, and Michelle Obama. Senator Obama will formally accept his party's nomination at an outdoor football stadium on the fourth night of the convention.

President Bush will speak at the Republican convention in Minnesota, but will do so early in the week so that the focus can shift to the presumptive nominee, Senator McCain and his yet to be chosen running mate.