US Democratic presidential candidates Senator Hillary Clinton (D-NY) and Senator Barack Obama (D-IL) pose before the last debate before the Ohio primary in Cleveland, Ohio, February 26, 2008. (Xinhua/Reuters Photo)

US Democratic presidential contenders Sen. Barack Obama of Illinois and Sen. Hillary Clinton of New York held their last debate Tuesday night in Cleveland, Ohio, before crucial March 4 primaries in Ohio and Texas that could make or break Clinton's campaign.

The pair traded punches on healthcare, trade agreement, foreign policy, Iraq and other key issues.

Clinton objected to Obama's accusation that she advocated measures to force all Americans to purchase healthcare coverage. Obama repeated the charge, describing her position as a "mandate" to buy coverage.