The U.S. presidential election campaign resumes this week after a pause out of respect for former President Ronald Reagan.

President Bush and his presumptive Democratic opponent in November, Senator John Kerry, are back on the campaign trail this week where the focus continues to be the situation in Iraq and the domestic economy.

Speculation is intensifying about who John Kerry will pick to be his vice presidential running mate on the Democratic Party ticket. Senator Kerry is expected to make that decision sometime before the Democratic Party's national nominating convention, which is being held the last week in July.

North Carolina Senator John Edwards, Missouri Congressman Richard Gephardt and Iowa Governor Tom Vilsack are reported to be those under consideration, though the Kerry campaign has refused comment on the vice presidential selection process.

Another name mentioned in recent weeks has been that of Republican Senator John McCain of Arizona, a longtime friend of Mr. Kerry's.

Senator McCain has repeatedly said he would not accept the vice presidential slot. But public opinion polls indicate a Kerry-McCain ticket would do well against President Bush and at least one Democrat, Senator Joe Biden of Delaware, thinks Senator McCain would be a good choice.

"I think everyone acknowledges, on the left, right and center, that we need to unite this country," said Mr. Biden on Fox News television Sunday. "We are much, much too divided. We are much too partisan, things have gotten much too bitter, and I think it would be a little bit like a unity government, and I think reaching out at this moment in our history, at this time with the difficulty we face, would be very much in the interest of the United States of America."

The New York Times reported Monday that momentum is building among other Senate Democrats for Senator Kerry to choose John Edwards as his running mate.

At the White House Monday, there was a rare break in the partisanship of the campaign when President Bush hosted former President Bill Clinton on the occasion of the unveiling of Mr. Clinton's official White House portrait. "Bill Clinton could always see a better day ahead, and Americans knew he was working hard to bring that day closer," said President Bush.

Former President Clinton took note of the president's kind words and said he hoped to find a way to ease the bitter partisan debates that have dominated national politics for the past several years.

"Most of the people I have known in this business - Republicans and Democrats, conservatives and liberals - are good people, honest people and they did what they thought was right," said Mr. Clinton, "and I hope that I will live long enough to see American politics return to vigorous debates where we argue who is right and wrong, not who is good and bad."

Mr. Clinton could have a further impact on this year's presidential campaign when his long awaited autobiography is released next week.