Republicans, for the most part, favor incentives that encourage coverage. Democrats prefer mandates that guarantee it. And each of the plans has at least one signature element that distinguishes it from the rest.
The year is 1993, when First Lady Hillary Clinton introduced a plan for universal health care that flopped miserably. But now, 15 years later, the senator and presidential hopeful says her new plan and its chances of passing are better.
The new initiative, called American Health Choices would allow the insured to keep their current plan while the 47 million uninsured Americans could elect coverage through the same private plan that's available to members of Congress.
Senator Barack Obama wants a national plan similar to what federal employees get, along with standards for the insurance industry so young adults can stay on their parents' plan until the age of 25.
Shared responsibility is Senator John Edwards' solution. His proposal for universal coverage requires businesses to provide insurance to their employees or contribute to a so-called health care market, a regional non-profit that would sell low-cost insurance to individuals.
On the Republican side, most of the candidates oppose universal health care and favor offering financial incentives to insurance companies to hold down costs.
Former governor Mitt Romney wants to redirect money now being spent on what he calls expensive free care for the uninsured in emergency rooms to help low-income families buy private insurance. He also wants to make all health-care expenses tax deductible.
Senator John McCain wants to give individuals a $2,500 tax credit, $5,000 for families, so it's easier to purchase private insurance. And they'll be able to do it through any organization: employers, professional associations, even churches.
The emphasis in former mayor Rudy Giuliani's plan is on the state, with block grants as incentives to reduce health care costs and enroll the uninsured.
The key to former governor Mike Huckabee's plan is a shift from a predominantly employer-based health care system to one that is driven primarily by consumers.
The candidates in both parties do agree on one thing: Medicare and Medicaid have to be protected for the 78 million baby boomers who become eligible in the coming years. But they disagree on the specifics of how to do that.
The price tag on the quasi-universal coverage promised by the Democrats is hundreds of billions of dollars to be paid for by, among other things, rolling back the Bush tax cuts to the wealthiest Americans.