In the U.S. presidential race, Barack Obama and John McCain are increasingly setting sights on each other as likely opponents in the November election.  But Obama's Democratic rival, Hillary Clinton, continues to battle for her party's nomination, despite long odds.  VOA national correspondent Jim Malone reports from Washington.

Assuming Senator Obama holds his delegate lead and becomes the Democratic nominee, the outlines of the general-election campaign are beginning to take shape.

Obama says little these days about rival Hillary Clinton, preferring instead to focus on the presumptive Republican nominee, Senator John McCain.

At every opportunity, Obama offers himself as a candidate of change and tries to tie McCain to President Bush, especially on issues like the war in Iraq and the weakened U.S. economy.

"We have had enough of the cannot do, will not do and will not even try approach from George Bush and John McCain," he said.  "We cannot afford another president who cannot be bothered to stand up for working people.  I believe it is time for a change.  It is time Washington went to work for working people, and that is why we are here today."

McCain is likely to face a difficult political climate in the general-election campaign.  President Bush's approval ratings are at an all-time low, and the public has negative views about the economy and the war in Iraq.

McCain is expected to focus on Obama's relative inexperience in national politics, and will question his ability to deal with military and national security issues.

For example, McCain questioned Obama's proposal to directly engage U.S. adversaries abroad in a recent speech on nuclear proliferation.

"Many believe that all we need to do to end the nuclear programs of hostile governments is to have our president sit down with leaders in Pyongyang and Tehran, as if we have not tried talking to these governments repeatedly over the past two decades," he said.

Other issues expected to receive attention during the campaign include health care, as well as relations with Iran and China.

Despite the growing focus on an Obama-McCain match-up in November, Obama first has to clinch his party's nomination over fierce rival Hillary Clinton.

Obama holds a virtually insurmountable lead in the delegate count.  But with three Democratic primaries to go, Clinton shows no signs of giving up.

"There are some who wish that this election had ended months ago, before you ever got a chance to vote," she said.  "I am not one of them.  The longer this election has gone on, the better I have done, so I am really excited about you voting here in Montana."

Obama expects to secure enough delegates to nail down the nomination sometime after the primaries end on June 3.  He will then have the task of unifying the party before he takes on John McCain in the general election.

Norman Ornstein is a political expert at the American Enterprise Institute in Washington.

"To bring people back into the fold, which will happen, you want them at least to feel as though the process worked its way through, and people did have a chance to vote," he said.

Recent public-opinion polls suggest a close race in November no matter which Democrat faces McCain.  A Gallup poll showed McCain leading Obama, 47 to 44 percent, while Clinton was ahead of McCain by a margin of 48 to 45 percent.