Obama vs. McCain: sharp differences on key issues

The two candidates have sharply different approaches to health care reform, which consistently ranks as the second-biggest domestic issue after the economy in national opinion polls.

McCain would use tax credits to help shift from employer-based insurance coverage to an open market system where people can choose from competing policies.

Obama would keep the existing job-based system and expand government involvement. He supports universal health coverage for the 47 million Americans without insurance, although he would only require coverage for children.

Health care, however, has not been a key factor in a presidential election since the collapse of the Hillary Clinton-led reform effort in 1994, and both candidates have emphasized other items.

McCain has repeatedly hammered Obama's lack of national security experience, criticizing his willingness to talk to leaders of hostile nations without preconditions as a sign of naivete.

Obama blasts McCain's economic leadership and his ties to Washington lobbyists, saying the Republican's presidency would amount to Bush's third term. Obama, who says McCain would prolong Bush's failed diplomatic approach, portrays the election as a choice between the future and the past.

Pollster John Zogby said every link drawn between the unpopular Bush and McCain would be a plus for Obama.

"Anything that reminds people of Bush hurts McCain, at least until he decides to step away from him and become a maverick again," Zogby said.

McCain has taken stances that put him at odds with many members of his party. His support for an overhaul of immigration laws angered some conservatives, although he softened his approach during the battle for the nomination.

Unlike Bush, McCain has addressed global warming as a legitimate problem and supports federal spending on stem-cell research.

"McCain has a chance to muddy up the differences on a few issues that have been politically helpful to Democrats in recent election cycles," Schnur said.

(Editing by David Wiessler)

(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)