Denver, Colorado - John Kerry, the Democrats' failed presidential candidate of 2004, made the case Wednesday that Barack Obama was ready to take over the party mantle and slammed the Republicans for claiming to have a lock on patriotism.

Kerry hammered presumptive Republican nominee John McCain for using the "same old politics of fear and smear" during the general election campaign, pointing to comments that questioned whether Obama puts the country ahead of personal politics.

"No one can question Barack Obama's patriotism," Kerry told the party convention gathering in Denver, Colorado, characterizing McCain's attacks as "desperate."

Kerry still showed some of the scars from his own bruising presidential campaign in 2004. That year, a political action group known as the Swift Boat Veterans for Truth released ads denigrating Kerry's own decorated military service in Vietnam, and was credited by many with winning the election for President George W Bush.

"You don't decide whose service counts and whose doesn't," Kerry said. The American flag "doesn't belong to any ideology ... it belongs to all the American people."

Kerry followed a long line of Democrats Wednesday that testified to Obama's ability to lead the United States on foreign policy, including a rousing speech by former president Bill Clinton.

Kerry, a Massachusetts senator who also sits on the Foreign Relations Committee in the upper legislative chamber, criticized Bush and the Republican Party for weakening what used to be agreement on foreign policy issues between the two parties, particularly for the 2003 invasion of Iraq.

"Never has short term partisan politics so depleted the strength of America's bipartisan foreign policy," Kerry said. (dpa)