Chicago: Barack Obama hasn't managed after months of political combat to force Hillary Clinton out of the presidential race, so he is about to try another approach: ignoring her.

Confident that Obama has built a nearly impenetrable lead, his campaign aides said on Thursday he will begin shifting his focus toward the general election.

Obama still plans to campaign in states that remain on the primary calendar - he is to appear in Oregon over the weekend - but he may also start showing up in states that are considered important in the November contest: Ohio, Florida and Pennsylvania All three have held Democratic primaries already.

Hubris

With Clinton's hopes of capturing the Democratic nomination dimming, Obama needs to prepare for the prospect of a general election matchup with the presumptive Republican nominee, Senator John McCain, aides said. Speaking to reporters aboard Obama's campaign plane late on Tuesday night, David Axelrod, the campaign's lead strategist, said: "Everyone is eager to get on with this." Axelrod added: "We've got to multi-task here. ... Senator McCain has basically run free for some time now."

Clinton's campaign cast Obama's strategy as a show of hubris. Clinton has given no signal she is dropping out of the race following the split results on Tuesday. Showing she still believes she can win, the New York senator hastily arranged a campaign stop on Wednesday in West Virginia, site of a primary on Tuesday.

"We've seen the perils of saying 'mission accomplished' too early," said Phil Singer, a Clinton campaign spokesman. The phrase "mission accomplished" was famously displayed on an aircraft carrier in 2003, when President George Bush came aboard and declared that major combat operations in Iraq had ended.