Senator Obama would prohibit insurance companies from denying coverage on the basis of health or age. He would mandate insurance for children. He also would require employers to cover their workers or pay a payroll tax to help subsidize government coverage for the uninsured. Some small businesses would be exempt, and would be offered tax credits to provide coverage for workers.



Mr. Obama would strive for universal coverage by establishing a new federal health plan for the uninsured, providing benefits comparable to those offered to federal employees. Premiums would be subsidized for low earners. Eligibility for other public programs — Medicaid and the State Children’s Health Insurance Plan — would be expanded. Mr. Obama also would establish a government exchange that would allow individuals to shop for the new public plan and approved private plans.



Among his proposals for controlling costs is a $50 billion investment in health information technology over five years.



Mr. Obama would pay for much of his plan by raising income taxes on those earning more than $250,000.

Senator McCain would upend the tax treatment of health benefits in order to give all consumers the same advantages, whether they purchase insurance through employers or not. He would eliminate the provision that allows workers to exclude their employer-sponsored benefits from taxable income, replacing it with tax credits worth $2,500 per individual and $5,000 per family. He also would let consumers purchase policies across state lines.



The McCain campaign argues that the tax changes will stoke competition in the individual market, lower prices and make coverage more affordable for the uninsured. Those with pre-existing health conditions who cannot obtain private insurance would be covered through a “guaranteed access plan.” It would put federal dollars behind the kinds of high-risk pools that currently operate in many states, often with inadequate financing.



Mr. McCain would seek to control health costs by limiting malpractice damages, investing in prevention and chronic-disease management, and encouraging the faster introduction of generic drugs, among other initiatives.